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NCERT Solutions of Social Science (SSt) - Class 6th

November 13, 2018, 5:10 am
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NCERT Solutions of Social Science - Class 6th (SSt) - Free PDF Download

Three textbooks on History, Geography and Civics are there in Class 6th Social Science. Each textbook deals with its subject field. This page will help you in finding NCERT Solutions of Class 6th Social Science which is given at the end of each chapter. The questions are for practising which will check your understanding of the chapter. In this page, you will find the number and type of questions that are given. The name of each textbook is provided through which you can browse NCERT Solutions.

NCERT Solutions of History Class 6th

NCERT Solutions of Geography Class 6th

NCERT Solutions of Civics Class 6th

Why opt for NCERT Solutions of Social Science on StudyRankers

At Studyrankers, we are striving hard to provide the best NCERT Solutions. Our expert faculty prepared these NCERT Solutions by going into information deeply. The type of question and marking scheme is followed while solving each question. Also, you can provide suggestions in comments if you find any answer not upto the mark so that we can make that better.

History NCERT Solutions Class 6th

There are total twelve chapters in the textbook which generally deals with the ancient Indian history. The book starts when human were merely gatherers and talks about the various kingdoms which came afterward. The first chapter talks about the dates, sources and events through which history is studied. In the second chapter, we will talk about the earliest phase of human life when they were gatherers. The third chapter will talk about the evolution of human from gathering food to growing food. The fourth chapter is focused on Indus valley civilisation while the fifth chapter is about Vedic civilisation. The sixth chapter talks about the republic and how the kingdoms started taking shape. The seventh chapter details the works of religious literature in brief. The eighth chapter is about the great emperor, Ashoka. Next chapter talks about the villages and towns of ancient times. The tenth chapter deals with the trading and pilgrims activities in ancient times. The eleventh chapter is about the rise of new kingdoms and empires in ancient India. The last chapter talks about the architectural and literary aspects of ancient India.

Geography NCERT Solutions Class 6th

In this textbook, we are mainly learning about the physical and India geography. There are eight chapters given in which first six chapters are part of physical geography while another two are focused on Indian geography. The first chapter is about the solar system of which our earth is part of. The second chapter will give you the concept of the globe. Next chapter talks about the motions of the earth. The fourth chapter is about maps. In the fifth chapter, we will talk about the major domains of the earth like lithosphere, hydrosphere, atmosphere and biosphere. In the next chapter, we will study about major landforms of the earth. In another next two chapter, we will talk about the location, features, climate, vegetation and wildlife of India.

Civics NCERT Solutions Class 6th

There are nine chapters divided under four units. In the first unit, we will try to understand diversity and how it affect us. The second unit will introduce us to the government and their elements. The third unit is focused on local government and administration. In the last unit we will discuss the rural and urban livelihoods.

Notes of Social Science Class 6th

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NCERT Solutions of Social Science (SSt) - Class 7th

November 14, 2018, 1:13 am
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NCERT Solutions of Social Science - Class 7th (SSt) - Free PDF Download

Social Science of upper primary classes just provides basic detail about the human society of past and present. This subject is divided into three parts, history, civics and geography. If you're finding any difficulty while preparing the NCERT Solutions of Social Science Class 7th textbook then you can take help from StudyRankers website. We put great effort while preparing these solutions so these can be accurate and detailed. You can start finding the solutions by choosing the subjects from the list given below.

NCERT Solutions of History Class 7th

NCERT Solutions of Civics Class 7th

NCERT Solutions of Geography Class 7th

History NCERT Solutions Class 7th

The textbook is divided into ten chapters and focused on the Medieval history of India. In the first chapter, we will study the time period and sources of Medieval India. The second chapter is about the tripartite struggle. The third chapter talks about the various kingdoms of Delhi Sultanate. In the next chapter, we will study the Mughal empire. In the fifth chapter, we will study the architectural aspects of the Medieval period. The sixth chapter is about the trading activities during this period. The next chapter is about the tribals, nomads and settled communities. The eighth chapter talks about the religious aspects of that period while the next chapter is about the cultural aspects. The last chapter is about the new political equations forming in India.

Civics NCERT Solutions Class 7th

There are five units in the textbook. The first unit about equality in Indian democracy. The second unit talks about the functioning of the state government and its role in providing health facilities. The third unit deals with gender equality. The fourth unit gives us an understanding of media and advertisement. Next unit is about how markets work. The last chapter is focused on the struggle for equality.

Geography NCERT Solutions Class 7th

There are ten chapters in this textbook. The first chapter is about the components of the environment. The second and third chapter deals with the study of the earth. The fourth and fifth chapter talks about air and water respectively. The sixth chapter is about the Natural Vegetation and Wildlife. The seventh and eighth chapter deals with the human environment. The last two chapters deals with the Life in the Temperate Grasslands and in the Deserts respectively.

Notes of Social Science Class 6th

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Extra Questions for Class 9th: Ch 6 Tissues Science

November 16, 2018, 7:02 am
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Extra Questions for Class 9th: Ch 6 Tissues (Science) Important Questions Answer Included

Very Short Answer Questions (VSAQs): 1 Mark

Q1.What is meristematic tissue?
Answer
Meristematic tissue is capable of dividing and is found in the developing regions of the plant.

Q2. What do you understand by differentiation ?
Answer
When meristematic tissues lose their ability to divide and become permanent in shape, size and function, the process is called differentiation.

Q3. What are stomata?
Answer
Stomata are the small pores present in the epidermis of leaf.

Q4. What do you mean by guard cells ?
Answer
Stomata are enclosed by two kidney-shaped cells which are called guard cells.

Q5. What are vascular bundles?
Answer
Vascular bundles consist of xylem and phloem.

Q6. Name the tissue which is responsible for increase in length of stem and root.
Answer
Apical meristem.

Q7. What is the function of RBCs?
Answer
Transportation of oxygen and carbon dioxide and pH constancy.

Q8. What is the life span of human RBCs ?
Answer
About 120 days.

Short Answer Questions-I (SAQs-I) : 2 Marks

Q1. (a) What is a tissue? Justify that blood is a tissue.
(b) Identify the meristematic tissues which are located at:
(i) Growing tips of roots and stems.
(ii) The base of the leaves or internodes on

Answer

(a) A group of cells that are similar in structure and work together to achieve a particular function is called a tissue. Blood is a cluster of similar cells and they perform same function in the body, hence blood is a tissue.

(b) (i) Apical meristem.
(ii) Intercalary meristem.

Q2. What is apical meristem? What is its function?

Answer

Apical meristems are the meristematic tissues which are found at the growing tips of stems and roots. It increases the length of the stems and roots and is responsible for the growth of plant.

Q3. Name the living component common to both the complex permanent tissues found in plants. What is its function?

Answer

Living component common to xylem and phloem tissues is parenchyma. Its function is to store food and help in sideways conduction of water in xylem and food in phloem.

Q4. Name the tissue that makes husk of coconut. Write three characteristics of this tissue.

Answer

Sclerenchymatous tissue. The cells are dead with long and narrow walls thickened due to lignin.

Q5. What is apical meristem? Where is it located? State its functions.

Answer

Apical meristem is a kind of meristematic tissue which is present at the growing tips of stems and roots. It increases the length of the stem and the root. These cells are responsible for linear growth of an organ.Example: Root apical meristem and Shoot apical meristem.

Q6. Name the following tissues:
(i) The connective tissue found between the skin and muscles.
(ii) The tissue which connects two bones.
(iii) The epithelial tissue which forms the lining of the kidney tubules.
(iv) The tissue which is present in the veins of leaves.

Answer

(i) Aerolar
(ii) Ligament
(iii) Cuboidal epithelium
(iv) Sclerenchyma.

Short Answer Questions-II (SAQs-II) : 3 Marks

Q1. Classify meristematic tissues on the basis of the region they are present. Also mention their functions.

Answer

Apical meristems-increase length of stem + roots.
Lateral meristems-increases girth.
Intercalary meristems-increase length, internodes.

Q2. (i) Name the tissue in the following figure:

(ii) Identify the parts ‘A’, ‘B’, ‘C’ and ‘D’.

Answer

(i) Phloem.
(ii) ‘A’–Sieve plate, ‘B’–Sieve tube, ‘C’–Phloem parenchyma, ‘D’–Companion cell.

Q3. List two characteristics of cork. How is it formed? Mention its role in trees.
Or
List the characteristics of cork. How are they formed?

Answer

Mention their role.
(i) Non-living
(ii) Compactly arranged
(iii) No intercellular spaces
A strip of secondary meristem replaces the epidermis. Cells on the outside are cut forming cork. Protection, makes the plant impervious to gases prevents loss of water, prevents mechanical injury or infection.

Q4 (i) State one point of difference between xylem and phloem. 
(ii) Draw a neat diagram of xylem vessel and a tracheid.

Answer

(i)Xylem conducts water in the plant body. Phloem transports food in the plant body.
(ii)


Q5. Label the following and give one function of each part labelled (i), (ii) and (iii)
Answer

(i) Lateral meristem: for increase in growth of plant parts.
(ii) Intercalary meristem: for formation of leaves, branches etc.
(iii)Apical meristem: increases length of the stem and the root.
Long Answer Questions (LAQs) : 5 Marks

Q1. Identify the following tissues:
(i) The epithelial tissue which has pillar like tall cells?
(ii) The cells of this tissue are filled with fat globules.
(iii) The movement of this tissue pushes the mucus forward to clear respiratory tract.
(iv) It gives buoyancy to lotus to help it afloat.
(v) Tissue present in lung alveoli.

Answer

(i) Columnar
(ii) Adipose
(iii) Ciliated columnar
(iv) Aerenchyma
(v) Squamous.

Q2. (a) Analyse the reason behind the following statements:
(i) Epidermis is thicker in desert plants though it is usually single layered.
(ii) Presence of waxy layer (secreted by epidermis) on the outer surface of plants.
(b) Discuss the cell arrangement which supports the fact that epidermis is a protective tissue.

Answer

(a) (i) In desert habitat, protection against water loss is essential. Epidermis is thick in desert plants and are covered with waxy cuticle layer in order to avoid excess loss of water through transpiration due to excess heat.
(ii) The waxy covering aids in protecting the plant against loss of water, mechanical injury and invasion by parasitic fungi.

(b) Epidermis is the outermost covering of cells in plants. It is usually made up of a single layer of cells. On aerial parts of a plant epidermal cells often secrete a waxy, water resistant layer on their outer surface to prevent loss of water from plant. The cells of epidermis are present in a continuous layer without intercellular spaces. Small pores are present on the epidermis of leaf. These pores are called as stomata, which help in gaseous exchange and transpiration. As the plant grows older, a strip of secondary meristem replaces the epidermis of stem and forms a thick cork.
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NCERT Solutions of Social Science (SSt) - Class 8th

November 16, 2018, 4:44 pm
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NCERT Solutions of Social Science - Class 8th (SSt) - Free PDF Download

Social Science is one of the main subjects in Class 8th which can't be ignored. This subject helps us to understand the human, society, government and its administration as well as about the different types of resources. NCERT Solutions in Social Science Class 8th textbook given at the end of each chapter help in checking our understanding of the chapter. We have covered all those questions with their solution so that you find them easily. You can browse the catalog of NCERT Solutions on this page by clicking on the subjects of History, Geography and Civics links.

NCERT Solutions of History (Part I) Class 8th

NCERT Solutions of History (Part II) Class 8th

NCERT Solutions of Geography Class 8th

NCERT Solutions of Civics Class 8th

History NCERT Solutions Class 8th


The history Chapter is divided into two books namely, Our Past Part I and II. Both books are focused on the events of modern Indian history. The first part is divided into six chapters. The first chapter talks about the significance of dates. The second chapter is about the events through which company established their power in India. Next chapter is about how the company exploited the countryside for their own benefits. The fourth chapter deals with the lives of tribals and affects of the rules made by the Britishers over them. Next chapter talks about the revolt of 1857. The last chapter deals with the condition of cities under colonial rule.

The second part is divided into six chapters. The seventh chapter talks about the condition of workers. The eighth chapter is about the education system adopted during the colonial rule. The ninth chapter is associated with the various reforms introduced by the Britishers and social workers. The tenth chapter deals with the art aspects. The eleventh chapter is about the talk about all the happenings during the 1870s - 1947. The last chapter is about the condition of India after Independence.

Geography NCERT Solutions Class 8th

The geography textbook is divided into six chapters. The first chapter is resources in which we will talk about the types of resources and ways to conserve them. The second chapter is about Land, Soil, Water, Natural Vegetation and Wildlife Resources. In the next chapter, we will talk about mineral resources. The fourth chapter deals with agriculture in which we will study types of farming. The fifth chapter is about industries. The last chapter is about human resources.

Civics NCERT Solutions Class 8th

There are ten chapters in the civics textbook. The first chapter is the Indian constitution in which we will study features and need of constitution. The second chapter deals with the concept of secularism. In the next chapter, we will understand the need of parliament in our country. The fourth chapter talks about the various laws of the country. In the next chapter, we will understand the concept of the judiciary. Chapter six helps us in understanding the criminal justice system of India through a case study. In chapter seven, we will study the marginalised society while in the next chapter, we will understand the ways through which we are confronting marginalised society. The unit five contains two chapters, nine and ten talks about the public facilities.

Notes of Social Science Class 8th

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NCERT Solutions of Social Science (SSt) - Class 10th

November 18, 2018, 4:04 am
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NCERT Solutions of Social Science - Class 10th (SSt) - Free PDF Download

The four subjects; history, political science, geography and economics are different parts of social science. After reading each chapter, we have to solve the questions given at the end which are called NCERT questions. These are very important for the preparation of exams so if you are finding any difficulties while solving any question then you can refer to this page. The NCERT Solutions of Social Science Class 10th textbook provided by us are detailed and accurate to the point.

NCERT Solutions of History Class 10th

NCERT Solutions of Civics Class 10th

NCERT Solutions of Geography Class 10th

NCERT Solutions of Economics Class 10th

History - NCERT Solutions Class 10th

There are eight chapters divided into three sections. The first section contains three chapters, each detailing nationalism movements in various countries. The fourth chapter talks about the ways through which world became a connected place. Next chapter is about industrialisation. In the sixth chapter, we will try to understand the lives of people in cities. The seventh chapter is about the introduction of the printing method and how it helped in shaping a new world. The last chapter talks about the world of novels.

Civics - NCERT Solution Class 10th

There are total eight chapters in this textbook. The first two chapters deal with the concept of power sharing which is a very essential feature of a democracy. In the third chapter, we will learn about social differences, divisions and inequalities and the way democracy deals with this. In the next chapter, we will discuss the inequalities based on gender, religion and caste. The fifth chapter is about popular struggles and movement that happened in the parts of the world. The sixth chapter tells us about political parties, its functions and various political parties present in India. The last two chapter tells the outcomes of democracy and the challenges it faces.

Geography - NCERT Solutions Class 10th

There are seven chapters in geography. The first chapter talks about the types of resources. and about the concept of development. The second chapter is about forests and wildlife while the third is about water resources. The fourth chapter talks about the types of farming and food crops produced in India. The fifth chapter deals with minerals and energy resources. The sixth chapter is about the secondary sector, industries. The last chapter deals with transportation and communication systems.

Economics - NCERT Solutions Class 10th

The first chapter talks about the developmental goals and its various characteristics. The next chapter deals with the sectors of the Indian economy. The third chapter is about the various forms of money and credits. The fourth chapter detailed the concept of globalisation and its effects on Indian economy. The last chapter is about the consumer rights.

Notes of Social Science Class 10th 

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Extra Questions for Class 9th: Ch 7 Diversity in Living Organims Science

November 19, 2018, 10:26 pm
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Extra Questions for Class 9th: Ch 7 Diversity in Living Organisms (Science) Important Questions Answer Included

Very Short Answer Questions (VSAQs): 1 Mark

Q1. Scientist who classified animals, according to whether they lived on land, in water or in air?
Answer
Greek thinker Aristotle classified animals, according to whether they lived on land, in water or in air.

Q2. What is the lowermost category in the hierarchy of classification of groups of organisms?
Answer
Species.

Q3. In the hierarchy of classification, which group will have - the smallest number of organisms with a maximum number of characteristics and the largest number of organism?
Answer
Smallest number of organisms – Kingdom.
Largest number of organisms – Species.

Q4. Name the kingdom in which an organism does not have a well-defined nucleus and organelles.
Answer
Monera.

Q5. In which kingdom would you place an organism which is unicellular, eukaryotic and photosynthetic?
Answer
Protista.

Short Answer Questions-I (SAQs-I) : 2 Marks

Q1. Mention any two advantages of classifying organisms.
Or
Why do we classify organisms?

Answer

(i) Classification makes the study of vast diverse of organisms easier by clubbing them into different groups.
(ii) It also facilitates the study of evolution that has taken place.

Q2. Which organisms are called primitive?

Answer

Primitive: Groups of organisms with simpler body structure and ancient body design that have not changed much over a period of time or with evolution e.g., amoeba.

Q3. How primitive organisms are they different from the advanced organisms?

Answer

Advanced Groups of organisms with complex body structure and design, that have changed over evolutionary time. e.g., Starfish. Amoeba has a simple body structure and primitive features to that of starfish. Hence, an amoeba is considered more primitive than starfish.

Q4. Name the first four categories used in hierarchical classification of organisms.

Answer

(i) Kingdom
(ii) Phylum/ Division
(iii) Class
(iv) Order

Q5. What is symbiotic relationship?

Answer

Some fungal species live in a permanent mutually dependent relationship with blue-green algae/Cyanobacteria. Such relationships are called symbiotic relationship.

Short Answer Questions-II (SAQs-II) : 3 Marks

Q1. What is the system of scientific naming of organisms called? State two important conventions followed while giving such names.

Answer

The system of scientific naming of organisms is called binomial nomenclature. Each name consists of two parts, generic name and specific name. Generic name should start in capitals and specific name in small letters. When printed, the specific name is given in italics, when handwritten, generic name and specific name must be underlined separately.

Q2. On the basis of presence or absence of coelom organisms are of two types. Is it true or false?

Answer

False. On the basis of presence or absence of coelom organisms are of three types. They are:
(i) Acoelomates
(ii) Coelomates
(iii) Pseudo coelomate

Q3. Carolus Linnaeus gave the two kingdom classification. Later it was changed by Ernst Haeckel in 1894 and in 1959, Whittakar gave the five-kingdom classification. Do you think that studying about the work done by earlier scientists or their obsolete theories is useful for students of this generation? Give any three reasons.

Answer

It helps us in:
(i) Learning the importance of observation.
(ii) Learning to value the efforts put in by the other scientists/people in general.
(iii) Developing scientific attitude/critical thinking.

Q4. Write four characteristics of monerans.

Answer

(i) They are unicellular.
(ii) Prokaryotic in nature.
(iii) Membrane bound cell organelles are absent.
(iv) The mode of nutrition is autotrophic.

Q5. Bluegreen algae have been included under the kingdom monera not under plantae. Why?

Answer

Plantae show definite membrane-bound organelles and multi-cellular body design. Blue-green algae is prokaryotic in nature as it does not show multicellular body design. Hence it is included in monera.

Long Answer Questions (LAQs) : 5 Marks

Q1. (a) State two basis of classifying plants and animals into different categories.
(b) List three characteristic features of fungi. Some fungal species live in permanent, mutually dependent relationships with cyanobacteria. What is this relationship called? Where are they found?

Answer

(a) (i) On the basis of cell structure.
(ii) On the basis of body organisation.

(b) Fungi are heterotrophic eukaryotic, saprophytes. Permanent mutually dependent relationships are called symbiotic relationships. They are found as slow, growing large, coloured patches on the bark of trees.

Q2. In vertebrata notochord is replaced by…..? State all features possess by vertebrata.

Answer

In vertebrata notochord is replaced by a true vertebral column. These animals have a true vertebral column and internal skeleton. All chordates possess the following features:
(i) Bilaterally symmetrical.
(ii) Have a notochord.
(iii) Have a dorsal nerve cord.
(iv) Are triploblastic, have paired gill pouches.
(v) Complex differentiation of body tissues and organs : paired gill pouches and 2, 3, 4 chambered heart
(vi) Are coelomate and segmented
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Extra Questions for Class 9th: Ch 8 Motion Science

November 20, 2018, 10:28 pm
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Extra Questions for Class 9th: Ch 8 Motion (Science) Important Questions Answer Included

Very Short Answer Questions (VSAQs): 1 Mark

Q.1. The phenomenon of motion was placed on a sound scientific footing by two scientists. Write their names.
Answer
Galileo Galilei and Isaac Newton.

Q.2. Are rest and motion absolute or relative terms?
Answer
They are relative terms.

Q.3. Suppose a ball is thrown vertically upwards from a position P above the ground. It rises to the highest point Q and returns to the same point P. What is the net displacement and distance travelled by the ball?
Answer
Displacement is zero. Distance is twice the distance between position P and Q.

Q.4. Which speed is greater: 30 m/s or 30 km/h?
Answer
30 m/s

Q.5. What do you mean by 2 m/s2?
Answer
The velocity of the body increases by 2 m/s after every second.

Q.6. Can uniform linear motion be accelerated?
Answer
No

Q.7. Define one radian.
Answer
It is the angle which is subtended at the centre by an arc having a length equal to the radius of the circle.

Q.8. What is the relation between linear velocity and angular velocity?
Answer
Linear velocity = Angular velocity x Radius of circular path.

Short Answer Questions-I (SAQs-I) : 2 Marks

Q. 1. Give an example of a body which may appear to be moving for one person and stationary for the other.

Answer

The passengers in a moving bus observe that the trees, buildings as well as the people on the roadside appear to be moving backwards. Similarly, a person standing on the roadside observes that the bus (along with its passengers) is moving in forward direction. But, at the same time, each passenger in a moving bus or train observes, his fellow passengers sitting and not moving. Thus, we can tell that motion is relative.

Q. 2. How can we describe the location of an object?

Answer

To describe the position of an object we need to specify a reference point called the origin. For example, suppose that a library in a city is 2 km north of the railway station. We have specified the position of the library with respect to the railway station i.e., in this case, the railway station acts as the reference point.

Q. 3. What do you mean by average speed? What are its units?

Answer

Average speed is defined as the average distance travelled per unit time and is obtained by dividing the total distance travelled by the total time taken. The unit of average speed is the same as that of the speed, that is, ms-1.

Q. 4. What is the difference between uniform velocity and non-uniform velocity?

Answer

Uniform velocity: An object with uniform velocity covers equal distances in equal intervals of time in a specified direction, e.g., an object moving with speed of 40km h-1 towards west has uniform velocity.
Non-uniform velocity: When an object covers unequal distances in equal intervals of time in a specified direction, or if the direction of motion changes, it is said to be moving with a non-uniform or variable velocity, e.g., revolving fan at a constant speed has variable velocity.

Short Answer Questions-II (SAQs-II) : 3 Marks

Q.1. Differentiate between distance and displacement.

Answer

Distance
Displacement
It is the length of the actual path covered by an object, irrespective of its dirction of motion.Displacement is the shortest distance between the initial and final positions of an object in a given direction.
Distance is a scalar quantity Displacement is a vector quantity. Displacement may be positive negative or zero.
Distance between two given points may be same or different for different path chosen.Displacement between two given points is always the same.
Distance covered can never be negative. It is always positive or zero.Displacement between two given points is always the same.

Q.2. What are the uses of a distance-time graph?

Answer

The various uses of a distance-time graph are as follows:
(a) It tells us about the position of the body at any instant of time.
(b) From the graph, we can see the distance covered by the body during a particular interval of time.
(c) It also gives us information about the velocity of the body at any instant of time.

Long Answer Questions (LAQs) : 5 Marks

Q.1. With the help of a graph, derive the relation v = u + at.

Answer

Consider the velocity-time graph of an object that moves under uniform acceleration as shown in the figure (u≠0).


From this graph, we can see that initial velocity of the object (at point A) is u and then it increases to v (at point B) in time t. The velocity changes at uniform rate a. As shown in the figure, the lines BC and BE are drawn from point B on the time and the velocity axes respectively.

The initial velocity is represented by OA.
The final velocity is represented by BC.
The time interval t is represented by OC.

BD = BC - CD, represents the change in velocity in time interval t.

If we draw AD parallel to OC, we observe that BC = BD + DC = BD + OA

Substituting, BC with v and OA with u, we get

v = BD + u
or, BD = v - u --- (i)

Thus, from the given velocity-time graph, the acceleration of the object is given by Change in velocity
a = (Change in velocity)/(Time Taken)= BD/AD= BD/OC
Substituting OC with t, we get
a = BD/t ⇒ BD = at --- (ii2)

From equations (1) and (2), we have
v-u = at or v =u + at

Q.2. Obtain a relation for the distance travelled by an object moving with a uniform acceleration in the interval between 4th and 5th seconds.

Answer

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Extra Questions for Class 9th: Ch 9 Force and Laws of Motion Science

November 21, 2018, 10:55 pm
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Extra Questions for Class 9th: Ch 9 Force and Laws of Motion (Science) Important Questions Answer Included

Very Short Answer Questions (VSAQs): 1 Mark

Q1. State the meaning of recoil velocity of a gun?
Answer
The velocity with which a gun moves backward after firing a bullet is called the recoil velocity of a gun.

Q2. Name the force which is responsible for change in position or state of an object.
Answer
Unbalanced forces.

Q3. Name the unbalanced force which slows down a moving bicycle when we stop pedaling it.
Answer
Force of friction.

Q4. Give one point of difference between balanced and unbalanced forces.
Answer
When forces acting on a body from all sides are equal, they cancel effect of each other and are known as balanced forces. On the other hand, when forces acting on a body are not equal/do not cancel each other are called unbalanced forces.

Q5. Why does the sole of the shoe wears out?
Answer
Sole of the shoe wears out due to friction between sole of the shoes and earth’s surface.

Q6. Mass of a body is doubled. How does its acceleration change under a given force?
Answer
Acceleration becomes half.

Q7. Mention any two kinds of changes that can be brought about in a body by force.
Answer
Change in speed/change of direction/change of shape.

Q8. State two effects, a force can produce in a non rigid body fixed at a position.
Answer
Change its shape and size.

Short Answer Questions-I (SAQs-I) : 2 Marks

Q1. State the SI unit of pressure. Mention the unit which we use to measure pressure exerted by a gas. What do you understand by normal atmospheric pressure?

Answer

Pascal Atmosphere (atm)
Atmospheric pressure at sea level = 1 atm

Q2. Define SI unit of force. A force of 2N acting on a body changes its velocity uniformly from 2 m/s to 5m/s in 10s. Calculate the mass of the body.

Answer



Q3. (i) It is possible that the train in which you are sitting appears to move while it is at rest? Justify your answer. 
(ii) Can the train appear to be at rest while moving? Justify your answer.

Answer

(i) Yes, this is because of relative motion.
(ii) Yes. This is because of inertia. We are in state of motion when compared to the train so we feel that the train is moving when actually it is at rest.

Q4. While driving vehicle how the use of safety belts prevents accidents? To show that a body remains at rest unless acted upon by an unbalanced force, mention one situation from everyday life.

Answer

First law of motion-makes the forward motion slower during accidents.
Example: Pedaling of bicycle.
When we stop pedaling, the bicycle begins to slow down. This is again because of the friction forces acting opposite to the direction of motion. In order to keep the bicycle moving, we have to start pedaling again. It thus appears that an object maintains its motion under the continuous application of an unbalanced force.

Q5. Derive Newton’s first law of motion from the mathematical expression of the second law of motion.

Answer

Newton’s first law states that a body stays at rest if it is at rest and moves with a constant velocity unit if a net force is applied on it. Newton’s second law states that the net force applied on the body is equal to the rate of change in its momentum.
F= ma
F = m(v-u)/t
Ft = mv-mu
That is, when F = 0, v = u for whatever time, t is taken. This means that the object will continue moving with uniform velocity, u throughout the time, t. If u is zero than v will also be zero, i.e., object will remain at rest.

Q6. Why is it easier to stop a tennis ball in comparison to a cricket ball moving with the same speed?

Answer

Tennis ball is lighter (less mass) than a cricket ball. Tennis ball moving with same speed has less momentum (mass × velocity) than a cricket ball. It is easier to stop tennis ball having less momentum.

Short Answer Questions-II (SAQs-II) : 3 Marks

Q1.
What type of force is acting in the cases given above ?

Answer

(i) Accelerating unbalanced force.
(ii) No force.
(iii) Retarding unbalanced force.

Q2. A force of 5N produces an acceleration of 8 m/s2 in mass m1, and acceleration of 24 m/s2 is mass m2. What acceleration would be if both are tied together?

Answer



Q3. Two boys dropped sheets of paper from the top of the tower. One boy dropped his sheet of paper as such, while the other boy dropped it by changing it in the shape of a ball. Which sheet of paper will reach the ground first? Explain why? (Assume air-resistance negligible).

Answer

The sheet shaped in form of a ball falls before the open sheet. Because the open sheet experiences more air resistance due to its large surface-area and this restricts its fall.

Q4. What are the effects of the following on inertia of a body?
(i) If force is doubled
(ii) If density is halved
(iii) If volume is reduced to one third.

Answer

(i) No effect.
(ii) No effect.
(iii) No effect.

Q5. What type of motion is represented by each of the following graphs?

Answer

(i) Uniform motion.
(ii) Uniform accelerated motion.
(iii) Uniform motion.

Long Answer Questions (LAQs) : 5 Marks

Q1. What is meant by ‘inertia’? What are different types of inertia? Give two examples in each case.

Answer

Inability of the body to change by itself its state of rest or state of uniform motion is called inertia.
Types: Inertia of rest: e.g. :
(i) When a card is flicked with a finger the coin placed over it falls in the tumbler.
(ii) Only the carom coin at the bottom of a pile is removed when a fast moving carom striker hits it.
Inertia of motion: e.g. :
(i) When a moving bus stops suddenly, the luggage might slide towards the front side of the bus and fall.
(ii) We tend to fall forward when a bus suddenly stops.

Q2. (i) Define momentum. Write its S.I. unit.
(ii) How much momentum will an object of mass 10 kg transfer to the floor, if it falls from a height of 5 m (g =10 m/s2).
(iii) Explain how a karate player can break a pile of tiles with a single blow of his hand.

Answer

(i) Momentum is the product of mass and velocity.
SI unit of momentum is – kg m/s.
(ii) v2=u2+2gh
v2= (0)2+2(10)(5)
v2=100
∴v=10 m/s

(ii) Momentum=m×v
=10×10=100 kg m/s

(iii) The karate player strikes the pile of tiles with his hand very fast. In doing so, the large momentum of fast moving hand is reduced to zero in a very short time. This exerts a very large force on the pile of tiles which is sufficient to break them.

Q3. (a) State the law of conservation of momentum.
(b) Observe the following diagram and answer the questions given below:
(i) Which direction does the balloon move when the thread tied to its neck is removed and why?
(ii) State the conclusion drawn from this activity.

Answer

(a) When two or more bodies act upon one another their total momentum remains constant, provided no external forces are acting.

(b) (i) Air from inside the balloon escapes from the mouth of the balloon. Balloon moves in opposite direction that is from left to right.
(ii) Forces of action and reaction are equal and opposite.

Q4. (i) Two objects of masses 100 g and 200 g are moving along the same line and direction with velocities of 2 m/s and 1 m/s respectively. They collide and after the collision, the first object moves at a velocity of 1.67 m/s. Determine the velocity of second object.
(ii) If a man jumps out from a boat, the boat moves backwards. Why?

Answer

Let
(i) m1=100=0.1 kg
m2=200 g=0.2 kg
u1=2 m/s
u2=1m/s
v1=1.67 m/s

According to law of conservation of momentum
m1u1+m2u2= m1v1+ m2v2
0.1×2 + 0.2×1 = 0.1 ×1.67 + 0.2×v2
0.2 + 0.2 = 0.167 + 0.2 v2
v2 =1.165 m/s

(ii) It is based on Newton’s third law of motion. As boat is floating and is not fixed, so it moves backwards.

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Extra Questions for Class 9th: Ch 10 Gravitation Science

November 22, 2018, 12:53 am
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Extra Questions for Class 9th: Ch 10 Gravitation (Science) Important Questions Answer Included

Very Short Answer Questions (VSAQs): 1 Mark

Q1. Who discovered that force is the cause of motion?
Answer
Galileo Galilei.

Q2. Who formulated the universal law of gravitation?
Answer
Sir Issac Newton.

Q3. Which force causes the things to fall towards the earth?
Answer
Gravitational force.

Q4. Who found out the value of gravitational constant (G)?
Answer
Henry Cavendish.

Q5. What is the unit of gravitational constant (G)?
Answer
The unit of gravitational constant is Nm2Kg-2

Short Answer Questions-I (SAQs-I) : 2 Marks

Q1. Give reason-stone falls towards the earth but earth do not rise towards the stone.

Answer

Stone falls due to gravitational force exerted by the earth. Earth do not move towards the stone as the mass of earth is much more than that of the stone.

Q2. Account for the following:
(i) On moon, man feels lighter than earth.
(ii) Mass is scalar while weight is a vector quantity.

Answer

(i) Due to less gravitational force exerted by moon on man.
(ii) Mass do not have direction while weight has direction.

Q3. Name the positions on earth where the value of ‘g’ is
(i) Maximum
(ii) Minimum? Justify your answer.

Answer

On earth value of g is maximum at poles and minimum at the equator. At poles radius of earth is less so value of g is more, at equator radius of earth is more so value of g is less. g =

Q4. (i) What keeps the moon in uniform circular motion around the earth?
(ii) Why do astronauts in space feel weightless?

Answer

(i) Gravitational force between the moon and the earth keeps moon in uniform circular motion around the earth.
(ii) They do not exert any force/weight on their spaceship due to the absence of gravity in space.

Q5. State any four natural phenomena explained by universal law of Gravitation.

Answer

(i) The force that binds us to earth.
(ii) The motion of moon around earth.
(iii) The motion of planets around sun.
(iv) Formation of tides.

Q6. Explain what happens to the force between two objects if:
(i) The mass of one object is doubled ?
(ii) The distance between the object is tripled.

Answer

We know the force between two objects of mass m1 and m2 is given
(i) F = Gm1m2/d2 --- (i)
Let mass of first object m1 is doubled, then the gravitational force F' will be
F'=(G(2m1)m2)/d2 = 2(Gm1m2)/d2 = 2F  --- (from i)
So, the force is doubled.

(ii) If the distance is trippled, the new distance will be d/3
The graviational force now will be F'' = (m1m2)/(d/3)2 = 9m1m2/d2 = 9F
So, the force will be 9 times of initial force.

Q7. State two factors on which value of ‘g’ depends.

Answer

(i) Latitude of the place.
(ii) Mass of the earth. Value is maximum at poles and minimum at equator of the earth.

Short Answer Questions-II (SAQs-II) : 3 Marks

Q1. Explain :
(i) Universal gravitational constant
(ii) Free fall

Answer

(i) Universal gravitational constant is the constant ‘G’ appearing in Newton’s law of gravitation.
F=GMm/r2

where, F is the force between two masses m and M at a distance r apart. The numerical value of G is equal to 6.673×10-11Nm2 kg-2. The value of G was found out by Henry Covendish by using a sensitive balance.
(ii) Free fall: Whenever objects fall towards the earth under the gravitational force alone, we can say that the objects are in free fall. While falling there is no change in the direction of motion of the objects. But due to earth’s attraction, there will be a change in the magnitude of the velocity.

Q2. State the universal law of gravitation. Mention four phenomena which can be explained by this law.

Answer

(i) The force that binds us to earth.
(ii) The motion of the moon around the earth.
(iii) The motion of planets around the sun.
(iv) The tides due to the moon and the sun.

Detailed Answer: Universal law of gravitation states that the force of attraction between two objects is proportional to the product of their masses and inversely proportional to the square of the distance between them.
Four phenomena which can be explained by this law are:
(i) The force that binds us to earth.
(ii) The motion of the moon around the earth.
(iii) The motion of planets around the sun.
(iv) The tides due to the moon and the sun.

Q3. In which direction do the following forces act when an object is in motion? Explain with the help of an example. (i) Frictional force (ii) Gravitational force

Answer

(i) Frictional force: Backwards
Example: If a book slides across the surface of a desk, then the desk exerts a frictional force in opposite (i.e. backwards) direction of its motion.

(ii) Gravitational force: Downwards
Example: When we throw a ball in the air, it returns to the ground.

Q4. A man’s weight when taken at the poles is 600 N. Will his weight remain the same when measured at the equator? Will there be an increase or decrease is his weight? Explain .

Answer

No, his weight will not remain same as that at the poles. There will be a decrease in his weight at the equator. As the radius of the earth increases from the poles to the equator, the value of ‘g’ becomes greater at poles decreasing towards equator. Also, the force of gravity decreases from poles to the equator.

Q5. Give reasons:
(i) A piece of paper takes much longer to fall than a stone through the same distance, when both are dropped simultaneously from roof.
(ii) The mass is constant everywhere the weight keeps changing.
(iii) The value of ‘g’ keeps changing as we move away from the earth whereas value of ‘G’ remains constant all over the universe.

Answer

(i) This is because a piece of paper has larger surface area and therefore experiences more friction due to air than a stone which has less surface are.
(ii) Because acceleration due to gravity varies from place to place.
(iii) The value of g depends on Latitude of the place and the mass of the earth while G is called universal constant as its value remains constant at all the places in the universe.

Q6. In which direction do the following forces act when an object is in motion:
(i) Frictional force
(ii) Gravitational force
(iii) Centripetal force

Answer

(i) Backward
(ii) Downward
(iii) Towards the centre

Long Answer Questions (LAQs) : 5 Marks

Q1. (i) A bar of metal has a mass 200 g and a certain weight. Mass remains the same when weighed at equator but weight decreases. Why?
(ii) Differentiate between mass and weight. Write any three differences.

Answer

(i) Weight is dependent on gravitational force. Since, on equator, gravitational force is less, so the weight of the bar of metal decreases.

(ii) Difference between mass and weight.

Mass
Weight
Mass is the quantity of matter contained in the body. 
Weight is the force of gravity acting on the body.
It is the measure of inertia of the body.It is the measure of gravity.
Mass is a constant quantity.Weight is not a constant quantity. It is different at different places.

Q2. Write three points of differences between mass and weight. How much would a 70 kg astronaut weigh on moon? What would be his mass on the earth and on the moon?

Answer

Differences between mass and weight:

Mass
Weight
Mass is the quantity of matter contained in the body. 
Weight is the force of gravity acting on the body.
It is the measure of inertia of the body.It is the measure of gravity.
Mass is a constant quantity.Weight is not a constant quantity. It is different at different places.
Mass of astronaut on moon = 70kg.Value of g on moon = (value of g on moon on earth)/6

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Extra Questions for Class 9th: Ch 11 Work and Energy Science

November 23, 2018, 4:01 am
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Extra Questions for Class 9th: Ch 11 Work and Energy (Science) Important Questions Answer Included

Very Short Answer Questions (VSAQs): 1 Mark

Q1. What is the work done against the gravity when a body is moved horizontally along a frictionless surface?
Answer
Zero

Q2. When displacement is in a direction opposite to the direction of force applied, what is the type of work done?
Answer
Negative work.

Q3. A 40 kg girl is running along a circular path of radius 1 m with a uniform speed. How much work is done by the girl in completing one circle?
Answer
Zero

Q4. Seema tried to push a heavy rock of 100 kg for 200 s but could not move it. Find the work done by Seema at the end of 200 s.
Answer
Work done = 0 Since displacement, s = 0

Q5. Identify the kind of energy possessed by a running athlete.
Answer
Kinetic energy.

Short Answer Questions-I (SAQs-I) : 2 Marks

Q1. An electrical heater is rated 1200 W. How much energy does it use in 10 hours?

Answer

Electrical energy = Power × time taken
= 1.2 × 10 = 12 kWh

Q2. If an electric appliance is rated 1000 W and is used for 2 hours. Calculate the work done in 2 hours.

Answer

Work done = Energy consumed
Energy = Power × Time taken
= 1000 W × 2 hour
= 2000 W-hr or 2 kW-hour or 2 kWh

Q3. A man of mass 62 kg sums up a stair case of 65 steps in 12 s. If height of each step is 20 cm, find his power.

Answer

𝑃.𝐸. =𝑚𝑔ℎ
𝑚=62 𝑘𝑔, 𝑔=10 𝑚/𝑠2 , ℎ=65 × 20/100 =13 𝑚
𝑃.𝐸. =62 ×10 ×13 = 8060 𝐽
𝑃= (𝑃.𝐸.)/𝑡= 8060/12
= 671.67 𝑊

Q4. How is work done by a force measured? A porter lifts a luggage of 20 kg from the ground and puts it on his head 1.7 m above the ground. Find the work done by the porter on the luggage. (𝒈=𝟏𝟎𝒎/𝒔2)

Answer

Work done is product of force and displacement .
𝑊=𝐹×𝑠
𝑚=20 𝑘𝑔,
𝑔=10𝑚/𝑠2,
ℎ =1.7𝑚
𝑇ℎ𝑒𝑤𝑜𝑟𝑘𝑑𝑜𝑛𝑒𝑏𝑦𝑡ℎ𝑒𝑝𝑜𝑟𝑡𝑒𝑟=𝑚𝑔ℎ
=20×10×1.7=340 𝐽

Q5. The velocity of a body moving in a straight line is increased by applying a constant force F, for some distance in the direction of motion. Prove that the increase in the kinetic energy of the body is equal to the work done by the force on the body.

Answer

𝑣2−𝑢2=2𝑎𝑠
𝑠=[(𝑣2−𝑢2)/2𝑎]
𝐹=𝑚𝑎
𝑊=𝐹×𝑠
𝑊=𝑚𝑎 [(𝑣2−𝑢2)/2𝑎]
= 1/2 𝑚𝑣2−1/2 𝑚𝑢2
=(𝐾.𝐸.)final− (𝐾.𝐸.)initial

Short Answer Questions-II (SAQs-II) : 3 Marks

Q1. When a force retards the motion of a body, what is the nature of work done by the force? State reason. List two examples of such a situation.

Answer

The work done by the force is negative because the displacement is opposite to the direction of force applied.
Example: (i) Work done by the force of friction;
(ii) Work done by applying brakes.

Q2. When is the work done by a force said to be negative ? Give one situation in which one of the forces acting on the object is doing positive work and the other is doing negative work.

Answer

Negative work: When the force is acting opposite to the direction of the displacement, the work done by the force is said to be negative. When we lift an object, two forces act on the
(i) Muscular force: Doing positive work in the direction of the displacement.
(ii) Gravitational force: Doing negative work opposite to the direction of the displacement.

Q3. (a) Under what conditions work is said to be done?
(b) A porter lifts a luggage of 1.5 kg from the ground and puts it on his head 1.5 m above the ground. Calculate the work done by him on the luggage.

Answer

(a) (i) Force should be applied.
(ii) Body should move in the line of action of force.
(iii)Angle between force and displacement should not be 90°.

(b) Mass of luggage, m = 15 kg and displacement, s = 1.5 m. 
Work done, W = F×s = mg × s = 15 × 10 × 1.5 = 225 J

Q4. Four persons jointly lift a 250 kg box to a height of 1 m and hold it.
(i) Calculate the work done by the persons in lifting the box.
(ii) How much work is done for just holding the box ?
(iii) Why do they get tired while holding it ? (𝑔=10𝑚𝑠2)

Answer

(i) 𝐹=250×10=2500𝑁
𝑠=1 𝑚
𝑊=𝐹×𝑠=2500×1=2500𝐽

(ii) Zero, as there is no displacement.

(iii) To hold the box, men are applying a force which is opposite and equal to the gravitational force acting on the box. While applying the force muscular effort is involved, and so they feel tired.

Q5. A boy is pulling a cart by supplying a constant force of 8 N on a straight path of 20 m. On a round about of 10 m diameter he forgets the path and takes 1½ turns and then continues on the straight path for another 20 m. Find the net work done by the boy on the cart.
Answer

𝐹=8𝑁
𝑊𝑜𝑟𝑘𝑑𝑜𝑛𝑒, 𝑊=𝐹×𝑠
𝑊1= 8×20=160 𝐽
𝐷=10 𝑚
S𝑜𝑟𝑎𝑑𝑖𝑢𝑠, 𝐷/2=5𝑚

𝐶𝑖𝑟𝑐𝑢𝑚𝑓𝑒𝑟𝑒𝑛𝑐𝑒𝑜𝑓𝑎𝑐𝑖𝑟𝑐𝑙𝑒=2 πr
=2×22/7×5
=31.43

𝐷𝑖𝑠𝑡𝑎𝑛𝑐𝑒𝑖𝑛 1⁄2 𝑐𝑖𝑟𝑐𝑙𝑒= πr
= 22/7×5=15.71

𝑇𝑜𝑡𝑎𝑙𝑑𝑖𝑠𝑡𝑎𝑛𝑐𝑒𝑓𝑜𝑟 11⁄2 𝑐𝑖𝑟𝑐𝑙𝑒=31.43+15.71=47.14 𝑚
𝑊2=𝐹×𝑠=8 ×47.14=376 𝐽
𝑊3=20×8=160 𝐽

𝑇𝑜𝑡𝑎𝑙𝑤𝑜𝑟𝑘𝑑𝑜𝑛𝑒=160+376+160
696 𝐽

Long Answer Questions (LAQs) : 5 Marks

Q1. Calculate the electricity bill amount for a month of 30 days, if the following devices are used as specified:
(i) 2 bulbs of 40 W for 6 hours.
(ii) 2 tubelights of 50 W for 8 hours.
(iii) A TV of 120 W for 6 hours.
Given the cost of electricity is ₹2.50 per unit.

Answer

Given the cost of electricity is ₹2.50 per unit.
(i) 2 bulbs of 40 watts for 6 hrs.
Energy consumed by Bulbs 𝐸1 =2 ×40×6=480 𝑊=0.48 𝐾𝑤ℎ

(ii) Energy consumed by 2 tubelights 𝐸2=50×8 ×2=0.800 𝑘𝑊ℎ

(iii) 𝐸nergy consumed by TV E3=120×6=0.720 𝑘𝑊ℎ
𝑇𝑜𝑡𝑎𝑙𝐸𝑛𝑒𝑟𝑔𝑦 = 0.48+0.80+0.72=2.00 𝑢𝑛𝑖𝑡𝑠𝑟𝑎𝑡𝑒=2.50 𝑝𝑒𝑟𝑢𝑛𝑖𝑡
𝐶𝑜𝑠𝑡𝑝𝑒𝑟𝑑𝑎𝑦 = 2 ×2.50=5.00
𝐶𝑜𝑠𝑡 30 𝑑𝑎𝑦𝑠 = 5.00×30=150

Q2. (i) What is meant by mechanical energy? State its two forms. State the law of conservation of energy. Give an example in which we observe a continuous change of one form of energy into another and vice-versa.
(ii) Calculate the amount of work required to stop a car of 1000 kg moving with a speed of 72 km/h.

Answer

(i) Sum of kinetic energy and potential energy of an object is the total mechanical energy.
Its two forms are kinetic energy and potential energy.
Energy can neither be created nor be destroyed but can be transformed from one form to another. 1 Example is simple pendulum.

(ii) 𝑚=1000 𝑘𝑔, 
𝑢=72 𝑘𝑚/ℎ =72× 5/18 𝑚/𝑠 =20 𝑚/𝑠,𝑣=0,
𝐼𝑛𝑖𝑡𝑖𝑎𝑙𝑘𝑖𝑛𝑒𝑡𝑖𝑐𝑒𝑛𝑒𝑟𝑔𝑦 = 1/2 𝑚𝑣2
= 1/2 ×1000×202
= 200000 𝐽 = 2 × 105𝐽
𝐹𝑖𝑛𝑎𝑙𝐾.𝐸. = 0
W𝑜𝑟𝑘𝑑𝑜𝑛𝑒=𝑐ℎ𝑎𝑛𝑔𝑒𝑖𝑛𝐾.𝐸. =2×105 𝐽

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Extra Questions for Class 9th: Ch 12 Sound Science

November 25, 2018, 6:12 am
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Extra Questions for Class 9th: Ch 12 Sound (Science) Important Questions Answer Included

Very Short Answer Questions (VSAQs): 1 Mark

Q1. What is a supersonic speed?
Answer
When the speed of an object exceeds the speed of sound, it is said to travel in supersonic speed. For example, bullets, jet crafts etc., travel in supersonic speeds.

Q2. Which type of wave is a sound wave?
Answer
Longitudinal mechanical wave.

Q3. Why is sound wave called a longitudinal wave?
Answer
In a sound wave, the particles of the medium vibrate in the direction parallel to the direction of the propagation of disturbance. Hence, a sound wave is called a longitudinal wave.

Q4. A baby recognizes her mother by her voice. Name the characteristic of sound involved.
Answer
Quality or timbre

Q5. Which sound has higher pitch-guitar or car horn?
Answer
The frequency of the vibration of a sound produced by a guitar is greater than that produced by a car horn. Since the pitch of a sound is proportional to its frequency, the guitar has a higher pitch than a car-horn.

Short Answer Questions-I (SAQs-I) : 2 Marks

Q1. (i) Define the time period of a wave.
(ii) Give the relation among speed of sound v, wavelength λ and its frequency υ.
(iii) A sound wave travels at a speed of 339ms-1. If its wavelength is 1.5 cm, what is the frequency of the wave ?

Answer

(i) The time taken by two consecutive compressions or rarefactions to cross a fixed point is called the time period of a wave.

(ii) Speed of sound (v)=Wavelength(λ)×Frequency (u)
⇒ v = λu

(iii) Given, velocity, v = 339ms-1
Wavelength, λ=1.5 cm
= 1.5/100 m
We know,
Velocity = Wavelength × Frequency
Therefore, Frequency = Velocity/Wavelength= 339/(1.5/100)
= (339×100)/1.5
Frequency = 22600 Hz

Q2. (a) Write the factor on which pitch of a sound depends?
(b) Draw a diagram to represent sound of:
(i) High pitch
(ii) Low pitch, of the same loudness.

Answer

(a) The pitch of a sound depends on the frequency of vibration. The pitch of a sound is directly proportional to its frequency.

(b)



Q3. (a) Which wave property determines:
(i) Loudness,
(ii) Pitch.
(b) Why are the ceilings of concert halls curved?

Answer

(a) (i) Amplitude
(ii) Frequency.

(b) Ceiling of concert halls are curved so that sound, after reflection, reaches all the corners of the hall. The sound after reflection from the curved surface spreads evenly across the width of the hall.

Q4. A wave is moving in air with a velocity of 340 m/s. Calculate the wavelength if its frequency is 512 Hz.

Answer

Frequency = 512 Hz, Speed of the sound = 340 m/s
Since v= λ u
λ = v/u = 340/512 = 0.66m

Q5. A stone is thrown in a pond. 12 full ripples are produced in 1 second. If the distance between a crest and a trough is 10 cm, calculate the wavelength and velocity of the wave.

Answer

Given :
Distance between the crest and next trough = 10 cm
or λ/2=10
λ=20 cm=0.20 m
Velocity v=u × λ
=12 ×0.20
=2.40 m/s

Short Answer Questions-II (SAQs-II) : 3 Marks

Q1. When vertically jerk is given to a string, transverse waves are formed. Give three features of these waves.

Answer

Three features of transverse waves are:
(i) The particles of the medium vibrates at right angles to the direction of propagation of wave.
(ii) Transverse waves travels in the form of crests and troughs.
(iii) They cannot travel through vacuum.

Q2. List any three human activities that would lead to environmental pollution.

Answer

(i) Burning of wood.
(ii) Combustion of coal and petroleum fuels.
(iii) Use of chemicals in the form of fertilizers and pesticides.

Q3. (a) Name the type of waves that can travel in gases.
(b) Name the wave which can travel in solids, liquids as well as gas.
(c) At any instant, a compression is formed at a point. After how much time period
(i) a rarefaction,
(ii) a compression will be formed at the same point ?

Answer

(a) Longitudinal wave.
(b) Sound waves.
(c) If T is the time period of the wave then,
(i) After time interval T/2, the point will have a rarefaction
(ii) After time T, the point will have a compression.

Q4. (i) How are the wavelength and frequency of a sound wave related to its speed ?
(ii) Calculate the wavelength of a sound wave whose frequency is 220 Hz and speed is 440 m/s in a given medium.

Answer

(i) v = λf
(ii) λ = v/f= 440/220 = 2 m

Q5. When a stone is thrown into a pond what type of waves are produced? Draw its displacement time graph. Label crest, trough and wavelength on the graph.

Answer

When a stone is thrown into a pond, transverse waves are formed.



Long Answer Questions (LAQs) : 5 Marks

Q1. (a) Why are sound waves called mechanical waves? List two practical applications of reflection of these waves.
(b) A stone is dropped from the top of a tower 125 m high into a pond of water at the base of the tower. When is the splash heard at the top ? (𝒈=𝟏𝟎𝒎/𝒔2 𝒂𝒏𝒅𝒔𝒑𝒆𝒆𝒅𝒐𝒇𝒔𝒐𝒖𝒏𝒅 =𝟑𝟒𝟎𝒎/𝒔)

Answer

(a) Sound is produced by the vibration of objects. When objects vibrate, it collides with the molecules in the medium. This collision produces mechanical oscillations in the medium. Because of this, sound waves are known as mechanical waves.
(i) Megaphones, horns, musical instruments as trumpets etc.
(ii) Stethoscope.

(𝑏)𝑆𝑝𝑒𝑒𝑑𝑜𝑓𝑠𝑜𝑢𝑛𝑑=340𝑚/𝑠;
𝑔 = 10 𝑚/𝑠2;
𝑢 = 0;
ℎ = 125 𝑚;
𝑡 = ?
ℎ = 𝑢𝑡+ 1/2 𝑔𝑡2
125 = 0 + 1/2×10×𝑡2
∴𝑡 = 5𝑠
Let 𝑡1 be the time taken by the sound to reach top
𝑢 = 340 𝑚/𝑠,
ℎ = 125 𝑚, 𝑡1=?
𝑡1 = ℎ/𝑢 = 125/240 = 0.37𝑠
𝑆𝑝𝑙𝑎𝑠ℎ 𝑤𝑖𝑙𝑙𝑏𝑒ℎ𝑒𝑎𝑟𝑑𝑎𝑓𝑡𝑒𝑟𝑡+ 𝑡1 = (5+0.37)𝑠 = 5.37𝑠

Q2. A sound wave travelling in a medium is represented as shown in the figure:
(i) Which letter represents the amplitude of the sound wave?
(ii) Which letter represents the wavelength of the wave?
(iii) What is the frequency of the source of sound if the vibrating source of sound makes 360 oscillations in two minutes?
(iv) Calculate the time period of the source of sound.


Answer

(𝑖) 𝑥−𝑎𝑚𝑝𝑙𝑖𝑡𝑢𝑑𝑒

(𝑖𝑖) 𝑦−𝑤𝑎𝑣𝑒𝑙𝑒𝑛𝑔𝑡ℎ

(𝑖𝑖𝑖) 𝐹𝑟𝑒𝑞𝑢𝑒𝑛𝑐𝑦 , 𝑢=𝑁𝑢𝑚𝑏𝑒𝑟𝑜𝑓𝑜𝑠𝑐𝑖𝑙𝑙𝑎𝑡𝑖𝑜𝑛𝑠/𝑇𝑖𝑚𝑒
= 360/(2×60) = 3 𝐻𝑧

(𝑖𝑣)𝑇𝑖𝑚𝑒𝑝𝑒𝑟𝑖𝑜𝑑 , 𝑇=1/𝑢 =1/3𝑠

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Extra Questions for Class 9th: Ch 13 Why do we Fall ill Science

November 26, 2018, 11:36 pm
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Extra Questions for Class 9th: Ch 13 Why do we Fall ill (Science) Important Questions Answer Included

Very Short Answer Questions (VSAQs): 1 Mark

Q1. What is community health?
Answer
An aspect of health, which deals with the well-being (physical, mental and social) of people of a community is called community health.

Q2. How is a disease identified?
Answer
A doctor identifies a disease by its symptoms and signs.

Q3. Name the causative organism of cholera.
Answer
Vibrio cholerae.

Q4. Which disease is caused by Helicobacter pylori?
Answer
Peptic ulcers.

Q5. What is the primary cause of haemophilia?
Answer
Primary cause of haemophilia is change in chromosome sequence.

Short Answer Questions-I (SAQs-I) : 2 Marks

Q1. (i) What are communicable diseases? Write its one example.
(ii) How do these spread?

Answer

Diseases that can be spread from one person to another are called communicable diseases, e.g., cough and cold, Pneumonia.
They can spread through air, sneezing water or air contact.

Q2. Write two examples each of
(i) Viral diseases
(ii) Bacterial diseases

Answer

(i) AIDS, dengue fever
(ii) Tuberculosis, typhoid, cholera

Q3. Which of the following diseases will cause major ill-effects on general health - Elephantiasis, Cough and cold, Tuberculosis, Diarrhoea. What are such diseases called?

Answer

Elephantiasis and tuberculosis. Such diseases are called chronic diseases.

Q4. Name the causal organism of AIDS. Why a person suffering from AIDS cannot fight even very minor infections?

Answer

Causal organism: HIV 1. 
A person suffering from AIDS cannot fight even very minor infections because it damages the immune system of the person and damages its function.

Q5. State any four ways by which AIDS virus spreads from an infected person to a healthy person

Answer

Four ways by which AIDS virus spreads are:
(i) Sexual contact with infected person.
(ii) Pregnant mother to her foetus.
(iii) Blood contact with infected person.
(iv) Using needle or syringe of infected person.

Short Answer Questions-II (SAQs-II) : 3 Marks

Q1. (i) Write difference between acute and chronic diseases.
(ii) Pick out chronic diseases from the list given below: Japanese encephalitis, viral fever, common cold, tuberculosis.

Answer

Acute diseases: Diseases that last for only very short periods are called acute disease. e.g., common cold chronic diseases: Diseases that last for long time even as much as a life time are called chronic diseases. e.g., elephantiasis
Japanese encephalitis, tuberculosis are chronic diseases.

Q2. State the method of transmission of each of the following diseases:
(a) (i) Cholera 
(ii) AIDS
(iii) Malaria
(iv) Pneumonia
(b) Name the diseases a person will get if the disease causing microbes target the liver of a person.

Answer

(a) (i) Cholera — Contaminated water
(ii) HIV-AIDS — Sexual contact
(iii) Malaria — Mosquito/ anopheles female
(iv) Pneumonia — Air

(b) Jaundice

Long Answer Questions (LAQs) : 5 Marks

Q 1.(a) What kind of food is advised when we fall sick and why?
(b) Mention any three basic conditions required for good health.

Answer

(a) We should take bland and nourishing food. Such food does not contain fat, oil or spices, so digested easily. It provides sufficient energy and nutrients which are required for recovery and regeneration.

(b) Balanced diet
Personal hygiene
Clean surrounding
Clean food and water
Clean air
Exercises and relaxation
No addiction (Any three)

Q2. Justify the following statements:
(a) “Availability of proper and sufficient food would prevent from infectious diseases”
(b) “The general ways of preventing infection mostly relate to preventing exposure”. List three points of prevention of exposure.

Answer

(a) Yes, availability of proper and sufficient food prevents from infectious diseases because functioning of immune system will not be good if proper and sufficient food and nourishment is not available.
(b) Yes, the general ways of preventing infection mostly relate to preventing exposure because:
(i) For air borne microbes, we can prevent exposure by providing living condition that are not over crowded.
(ii) For water borne microbes, we can prevent exposure by providing safe drinking water.
(iii) For vector borne microbes we can prevent exposure by providing clean environment.

Q3. Explain the statement by giving two examples: ‘It is not necessary that the pathogen may affect an organ or tissue depending upon the point of entry’. 

Answer

The above statement implies that it is not necessary that, if the pathogen enters the body by different ways, it alters the site and consequence of infection.
For example:
• Suppose HIV virus enters through blood or sexual intercourse person will get HIV.

• If Japanese encephalitis causing virus enters blood through mosquito bite, it reaches brain on infection.

• Herpes simplex virus can enter body orally or through sexual contacts but they affect the body inspite of different point of entry.

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Extra Questions for Class 9th: Ch 14 Natural Resources Science

November 27, 2018, 9:24 pm
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Extra Questions for Class 9th: Ch 14 Natural Resources (Science) Important Questions Answer Included

Very Short Answer Questions (VSAQs): 1 Mark

Q1. Define the term ‘biosphere’.
Answer
Life supporting zone where atmosphere, hydrosphere and lithosphere interact.

Q2. List two biotic components of biosphere.
Answer
Plants and animals.

Q3. State the term used to describe bits of decayed living organisms present in soil.
Answer
Humus

Q4. Name any two air pollutants produced by burning of coal and petroleum.
Answer
SO2 and NO2


Q5. Suggest a way of bringing underground water to the surface of earth.
Answer
Wells or Tube wells.

Short Answer Questions-I (SAQs-I) : 2 Marks

Q1. Which symbiotic life forms can grow on stones and help in the formation of soil? Write the mode of their action for making soil from rocks.

Answer

Lichens is the symbiotic life forms. Lichens secrete organic acids, which develops cracks in stones.

Q2. Name two measures that can be taken to reduce water pollution.

Answer

Garbage should not be thrown into water bodies, all industrial wastes from the factories should be treated before releasing into river or water bodies.

Q3. Name the two gases given out by burning of fossil fuels which dissolve in rain water to form acid rain.

Answer

NO2 Nitrogen Oxygen
SO2 Sulphur Oxygen

Q4. Describe greenhouse effect.

Answer

A part of the sunlight that falls on the earth is reflected back in the form of infrared light. This infrared light is absorbed by the carbon dioxide molecules present in atmosphere. Due to increase in CO2 concentration in the atmosphere, larger proportion of the infrared rays is trapped by CO2 molecules. This phenomenon is called the greenhouse effect.

Short Answer Questions-II (SAQs-II) : 3 Marks

Q1. Name the three constituents of abiotic component of the biosphere. Explain their major role in biosphere.

Answer

Constituents of Abiotic component are:
(i) Soil or Lithosphere: Land (or soil) on the earth’s crust
(ii) Water or Hydrosphere: Water that covers 75% or crust
(iii) Air or Atmosphere: Blanket of gases that covers earth
The three provide support to all living organisms which constitute biotic component of biosphere.

Q2. How are clouds formed? Explain in detail.

Answer

Continuous evaporation of water.
Cooling of water vapour as it goes up and formation of droplets.
Low temperature brings about precipitation.

Q3. Water is essential for life? Why? State three points.

Answer

(i) It regulates body temperature.
(ii) All cellular processes take place in water medium.
(iii) Digestion of food;
(iv) transportation of nutrients through blood; excretion of waste.

Q4. The fish in a lake near an industrial city suddenly dies. State thee reasons.

Answer

Three reasons are:
(i) Addition of undesirable substances like pesticides, poisonous salts etc.
(ii) Removal of nutrients, depletion of oxygen.
(iii) Sudden change (rise) in temperature due to hot water released by factories.

Q5. State briefly three harmful effects of burning of fossil fuels.

Answer

(i) Presence of high levels of suspended particles like unburnt carbon particles in the atmosphere, cause visibility to be lowered. In cold weather when water condenses out of air. This forms smog.

(ii) It increases the incidences of allergies, cancer and heart disease.

(iii) On burning oxides of nitrogen and sulphur are formed. They dissolve in rains to give rise to acid rain.

Q6. (i) Though large oceans surround the land masses, the water needs to be conserved. Explain.
(ii) How is the life of organisms living in water affected when water gets polluted?

Answer

(i) Marine water is not useful for human and plant life directly, Uneven distribution of limited fresh water resources need conservation.

(ii) Dissolved waste in water cause pollution. It increases the temperature of water and availability of dissolved O2 in water gets reduced. It results in the death of aquatic life.

Long Answer Questions (LAQs) : 5 Marks

Q1. (i) How is gaseous nitrogen fixed by the plants?
(ii) Schematically depict nitrogen cycle in nature.
(iii) Mention any one difference between nitrogen fixation and nitrification.

Answer

(i) Nitrogen fixation.

(ii) Nitrogen Cycle

(iii) Nitrification is conversion of ammonia to nitrites/ nitrates. Nitrogen fixation is conversion of atmospheric nitrogen to compounds of nitrogen.

Q2. (a) Explain the Biological and physical methods of nitrogen fixation.
(b) (i) Complete the nitrogen cycle in nature by labelling ‘X’ and ‘Y’ in the biogeochemical cycle shown below.
(ii) Explain the part marked ‘X

Answer

(a) Biologically nitrogen is fixed by the bacteria living in the root nodules of leguminous plants and physically fix through lightning.

(b) (i) X = Denitrification, Y = Ammonification.

(ii) Denitrifying bacteria convert the nitrate compounds back to nitrogen which releases into the atmosphere. This process is called denitrification.



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Extra Questions for Class 9th: Ch 15 Improvement in Food Resources Science

November 29, 2018, 11:29 pm
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Extra Questions for Class 9th: Ch 15 Improvement in Food Resources (Science) Important Questions Answer Included

Very Short Answer Questions (VSAQs): 1 Mark

Q1. Name the process by which green plants make their own food.
Answer
Photosynthesis.

Q2. Mention any two food materials which provide us carbohydrates.
Answer
Potato and Rice.

Q3. Name two cattle breeds which show excellent resistance of diseases.
Answer
Red Sindhi and Sahiwal.

Q4. What is animal husbandry?
Answer
Animal husbandry is the scientific management of animal livestock and includes feeding, breeding and disease control.

Q5. What is the main benefit of mixed cropping? 
Answer
It reduces risk and gives some insurance against failure of one of the crops.

Short Answer Questions-I (SAQs-I) : 2 Marks

Q1. How is Inter-cropping different from Mixed cropping? Write any two differences.

Answer

Differences between Mixed cropping and intercropping:

Sl. No.
Mixed Cropping
Inter cropping
1.
There is no definite pattern of rows.Crops are grown in definite pattern of rows like 1: 1, 1: 2 or 1: 3.
2.It is undertaken to reduce the chances of crop failure.It is undertaken to enhance the production of crops per unit area.

Q2. Enumerate the advantages of mixed farming.

Answer

Following are the main advantages of mixed farming:

(i) The risk of complete crop failure is minimized due to undertain monsoon.
(ii) Higher yield is obtained with better soil fertility.
(iii) It provides work to all the members of a family throughout the year.
(iv) By adopting exact combination in mixed farming, a variety of produce can be obtained to fulfill family needs.

Q3. Why should the pesticides be used judiciously?

Answer

Pesticides are the chemicals that are used to control weeds, insects, rodents, fungi as well as diseases of plants. They include weedicides, insecticides and fungicides. Their excessive use cause environmental pollution. They reach the water resources by leaching and affect the aquatic flora and fauna. These harmful chemicals reach the bodies of birds, animals and human beings through the various food chains and are thus harmful to one and all. Hence, they should be used judiciously.

Q4. Why storage of grains leads to losses? What preventive and control measures are adopted befoer grains are stored for future use?

Answer

Due to biotic factors like insects, rodents, fungi, mites, bacteria and abiotic factors like inappropriate moisture and temperature in the place of storage, there is degradation in quality, loss in weight, poor germinability, discolouration of produce, all leading to poor marketability. So, preventive and control measures are used before grains are stored for future use, which include strict cleansing of the produce before storage, proper drying of the produce first in sunlight and then in shade and fumigations by using chemicals that kill pests.

Q5. How are crops selected for crop rotation?

Answer

Growing different crops on the same field or a piece of land in a pre-planned succession is called crop rotation.

For crop rotation, the selection of crops depends on the:
(i) Type of soil.
(ii) Nutrient status.
(iii) Availability of water through rain or irrigation.
(iv) Length of rainy season.
(v) Duration of crop-short or long, and
(vi) Availability of inputs like fertilizers, pesticides, manpower etc.

Short Answer Questions-II (SAQs-II) : 3 Marks

Q1. Name the environmental factors related to cultivation practices and crop yield. Explain how they are related to crop yield.

Answer

Weather: Climatic conditions should be favourable for the growth of crops, like duration of sunlight, temperature, rainfall etc.

Soil Quality: All plants require nutrients for their growth. Soil acts as a medium. Soil should be rich in nutrients and should have a balanced pH for the growth of the crops.

Availability of Water: Irrigation should be proper for the better production of crops.

Q2. Explain the ways by which crop-production can be increased.

There are three ways:

(i) Crop Variety Improvement: This approach aims at finding a crop variety that can give a good yield variety that can produce high yield under different conditions and can withstand different situations like weather changes, soil quality, water availability etc.

(ii) Crop Production Management: Farmers have to look into the financial aspect of a crop. They have to think about the capital to invest on the land and the benefits they get from it. It is the financial condition that allows farmers to grow a particular crop. The purchasing capacity for inputs decides cropping system and production practices.

(iii) Crop Protection Management: Field crops are infested by a large number of weeds, insect pests and diseases. If they are controlled at correct time, it will ensure increased crop production.

Q3. Define Animal husbandry. Why livestock production needs to be improved?

Answer

Animal husbandry can be defined as the science of rearing, feeding, caring, breeding and utilisation of animals.

Needs of improving livestock production:

(i) It is required to meet the increasing demands of animal based goods like milk, meat, egg, leather etc.

(ii) Animal husbandry sets guidelines for proper management and systematic approach to animal rearing.

(iii) It also helps in proper utilisation of animal wastes like animal dung.

Q4. List any three management practices while designing a shelter for cattle.

Answer

While designing a shelter for cattle we must have a shelter that is:

(i) Well ventilated
(ii) Protects animals from rain, heat and cold
(iii) The floor of the cattle shed needs to be sloping so as to stay dry and facilitate cleaning.

Q5. State two advantages of composite fish culture. What is the application of hormonal stimulation in fish culture?

Answer

Advantages of composite fish culture:

(i) It helps to get a variety in fish yield.
(ii) Food in the pond gets evenly used up due to different varieties of fish having different food habits present in a pond.
(iii) Fish do not compete for food as all type of fish get their kind of food. Hormonal stimulation ensures the supply of pure fish seed in desired quantities.

Q6. In what ways internal parasites like worms and flukes and external parasites cause harm to the cattels.

Answer

External parasite—skin disease,
worm—affect stomach and intestine;
Flukes—damage liver.

Long Answer Questions (LAQs) : 5 Marks

Q1. (a) List the various factors which are responsible for loss of stored food grains.
(b) How these factors affect the produce?
(c) What can be done to prevent this loss?

Answer

(a) Biotic — insects, rodents, fungi, mites, bacteria.
Abiotic—inappropriate moisture + temperature.

(b) (i) Degradation in quantity.
(ii) Loss in weight. 
(iii) Poor germinability 
(iv) Poor marketability

(c) (i) Drying first in sunlight, then in shade. (ii) Fumigation.

Q2. Describe in short five methods by which you can increase the yield of crops and livestock.

Answer

Five methods by which we can increase the yield of crops and livestock are as follows:

(i) By including better crop management like mixed farming, crop and fodder yields can be improved.

(ii) By improved varieties of seeds etc. and cropping practices, we can improve the yield of crops which indirectly provides improved food for livestock.

(iii) By minimizing the application of fertilizers and pesticides.

(iv) By adopting integrated farming practices, e.g., combining agriculture with livestock.

(v) By promoting the usage of livestock excreta for production of compost, we can supply required nutrients through soil.

Q3. Unpredictable monsoon/ droughts/ low rainfall is adversely affecting the Indian agriculture.
(a) Mention any two initiatives that have been adopted to increase the availability of water for agricultural purposes.
(b) State two advantages of making check dams.
(c) Briefly describe canal and river lift system of irrigation.

Answer

(a) Rain water harvesting and water shed management.

(b) Two advantages of check dams:
(i) Increase the ground water level
(ii) Reduce soil erosion
(iii)Prevent rain water from flowing away

(c) Canal system: From rivers /reservoirs to crop field through system of canals. River lift system: Water is drawn from rivers for supplementing irrigation.

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Notes of Ch 6 Kingdoms, Kings and an Early Republic| Class 6th History

November 30, 2018, 10:27 pm
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Notes of Chapter 6 Kingdoms, Kings and an Early Republic Class 6th History

How some men became rulers

• Around 3000 years ago, some men became recognised as rajas by performing very big sacrifices.

• The later rajas gained recognition by performing very big sacrifices.

• Ashvamedha or a horse sacrifice was an important ritual for a raja.
→ The raja who organised the sacrifice was recognised as being very powerful, and all those who came brought gifts for him.

Varnas

• The priests divided people into four groups called Varnas.

• According to them, each Varna had a different set of functions.

• These groups were decided on the basis of birth.

→ Brahmin: They were expected to study and teach the Vedas, perform sacrifices and receive gifts.
→ Kshatriyas: They were the rulers and were expected to fight battles and protect people.
→ Vish or the Vaishyas: They were expected to be farmers, herders and traders. Both the Kshatriyas and the Vaishyas could perform sacrifices.
→ Shudras: They had to serve the other three groups and could not perform any rituals. Often, women were also grouped with them. They were not allowed to study the Vedas.

Janapadas

• The rajas who performed these big sacrifices were recognised as being rajas of janapadas.

• The word janapada literally means the land where the Jana set its foot and settled down.

• Archeologists found that in janapadas, people lived in huts, kept cattle and other animals.
→ They also grew a variety of crops — rice, wheat, barley, pulses, sugarcane, sesame and mustard.

• They made earthen pots. Some were grey and others were red.
→ A special type of pottery found at these sites is known as Painted Grey Ware.

Mahajanapadas

• About 2500 years ago, some Janapadas became more important than others and were known as Mahajanapadas.

• Most mahajanapadas had a capital city, many of these were fortified which means that huge walls
of wood, brick or stone were built around them.

Taxes

• Rulers of the mahajanapadas needed more resources for building huge forts and maintaining armies.

• The started collecting regular taxes.

• Taxes were collected from farmers, craft persons, herders, traders, hunters as per their skills.

Changes in agriculture

• The growing use of iron ploughshares helped in more grain production.

• People began transplanting paddy which meant that instead of scattering seeds on the ground, from which plants would sprout, saplings were grown and then planted in the fields. This led to increased production, as many more plants survived.

A closer look — (a) Magadha

• Magadha became the most important mahajanapada in about two hundred years.

• Many rivers such as the Ganga and Son flowed through Magadha which helped in transport, water supplies and making the land fertile.

• Two powerful rulers of Magadha were Bimbisara and Ajatasattu.

• The first capital of Magadha was Rajagriha in Bihar and the second was Pataliputra.

A closer look — (b) Vajji

• Vajji, with its capital at Vaishali (Bihar), was under a different form of government, known as gana or sangha.

• In a gana or a sangha there were many rulers, each one was known as a raja.

• The rajas performed rituals together and met in assemblies.

• Women, dasas and kammakaras could not participate in these assemblies.

• Both the Buddha and the Mahavira belonged to ganas or sanghas.

• The last of the sanghas were conquered by Gupta rulers around 1500 years ago.

NCERT Solutions of Chapter 6 Kingdoms, Kings and an Early Republic

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Search

Notes of Ch 7 New Questions and Ideas| Class 6th History

December 3, 2018, 11:34 pm
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Notes of Chapter 7 New Questions and Ideas Class 6th History

The story of the Buddha

• Siddhartha, also known as Gautama, the founder of Buddhism, was born about 2500 years ago.

• He belonged to a small gana known as the Sakya gana, and was a kshatriya.

• When he was a young man, he left the comforts of his home in search of knowledge.

• He wandered for several years and meditated for days on end under a peepal tree at Bodh Gaya in Bihar, where he attained enlightenment.
→ After that, he was known as the Buddha or the Wise One.

• He then went to Sarnath, near Varanasi, where he taught for the first time.

• He spent the rest of his life travelling on foot, going from place to place, teaching people,
till he passed away at Kusinara.

• The Buddha taught that life is full of suffering and unhappiness which is caused because we have
cravings and desires.

• The Buddha taught in the language of the ordinary people, Prakrit, so that everybody could understand his message.

Upanishads

• These were part of the later Vedic texts.

• Upanishad literally means ‘approaching and sitting near’.

• They described the atman or the individual soul and the brahman or the universal soul that ultimately, were one.

• Most Upanishadic thinkers were men, especially brahmins and rajas.
→ There were also few women thinkers such as Gargi, who was famous for her learning, and participated in debates held in royal courts.

Jainism

• The last and 24th tirthankara of the Jainas, Vardhamana Mahavira was the most famous among all thinkers.

• He was a kshatriya prince of the Lichchhavis, a group that was part of the Vajji sangha.

• Followers of Mahavira, who were known as Jainas, had to lead very simple lives, begging for food.

• They had to be absolutely honest, and were especially asked not to steal.

• Jainism was supported mainly by traders.

• Over hundreds of years, Jainism spread to different parts of north India, and to Gujarat, Tamil Nadu and Karnataka.

• The teachings of Mahavira and his followers were transmitted orally for several centuries.
→ They were written down in the form in which they are presently available at a place called Valabhi, in Gujarat, about 1500 years ago

The sangha

• Both the Mahavira and the Buddha felt that only those who left their homes could gain true knowledge.

• They arranged for them to stay together in the sangha, an association of those who left their homes.

• Men and women who joined the sangha led simple lives.
→ They meditated for most of the time and went to cities and villages to beg for food during fixed hours.
→ That is why they were known as bhikkhus and bhikkhunis.

Monasteries

• Both Jaina and Buddhist monks went from place to place throughout the year, teaching people.

• Many supporters of the monks and nuns, and they themselves felt the need for more permanent shelters and so monasteries were built.
→ These were known as viharas.

• The land on which the vihara was built was donated by a rich merchant or a landowner, or the king.

• The local people came with gifts of food, clothing and medicines for the monks and nuns.


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Notes of Ch 8 Ashoka, the Emperor Who Gave up War| Class 6th History

December 7, 2018, 7:37 am
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Notes of Chapter 8 Ashoka, the Emperor Who Gave up War Class 6th History

A very big kingdom = an empire

• The empire (Mauryan empire) that Ashoka ruled was founded by his grandfather, Chandragupta Maurya, more than 2300 years ago.

• Chandragupta was supported by a wise man named Chanakya or Kautilya.

• There were several cities in the empire which included the capital Pataliputra, Taxila, and Ujjain. Taxila was a gateway to the northwest, including Central Asia, while Ujjain lay on the route from north to south India.

How are empires different from kingdoms?

• Emperors need more resources than kings because empires are larger than kingdoms, and need to be
protected by big armies.

• So also they need a larger number of officials who collect taxes.

Ruling the empire

• The officials were appointed to collect taxes from farmers, herders, crafts persons and traders, who lived in villages and towns in the area.
→ Officials also punished those who disobeyed the ruler’s orders.
→ Many of these officials were given salaries.

• Royal princes were often sent as governors of provinces which was ruled from a provincial capital such as Taxila or Ujjain.

• The Mauryas tried to control roads and rivers, which were important for transport, and to collect whatever resources were available as tax and tribute.

• People of forested regions were more or less independent, but may have been expected to provide elephants, timber, honey and wax to Mauryan officials.

Ashoka, a unique ruler

• The most famous Mauryan ruler was Ashoka.

• He was the first ruler who tried to take his message to the people through inscriptions which were in Prakrit and were written in the Brahmi script.

Ashoka’s war in Kalinga

• Ashoka was so horrified when he saw the violence and bloodshed in Kalinga's war that he decided
not to fight any more wars.

• He is the only king in the history of the world who gave up conquest after winning a war.

What was Ashoka’s dhamma?

• Ashoka’s dhamma did not involve worship of a god, or performance of a sacrifice.

• He felt that just as a father tries to teach his children, he had a duty to instruct his subjects.

• He was also inspired by the teachings of the Buddha.

• He appointed officials, known as the dhamma mahamatta who went from place to place teaching people about dhamma.

• Ashoka also sent messengers to spread ideas about dhamma to other lands, such as Syria, Egypt, Greece and Sri Lanka.


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NCERT Solutions for Class 12th: Ch 6 Staffing

December 13, 2018, 12:15 am
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NCERT Solutions for Class 12th: Ch 6 Staffing Business Studies I

Exercises

Page No: 175

Short Answer Type

1. Briefly enumerate the important sources of recruitment.

 Answer

There are two important sources of recruitment:

(i) Internal source:
(a) Transfer – It involves shifting of an employee from one job to another, one department to another from one shift to another, without a substantive change in the responsibilities and status of the employee.

(b) Promotions – Promotions is the part of the internal source of recruitment where companies filling higher job by promoting employees from lower job.

(ii) External source: It refer to the source of recruitment where companies filling the vacant sit from outside sources so, it is a very long and costly process. External source provides wide choice and brings new blood in the organisation which may sometimes useful and sometimes not. There are various types of sources used for external sources of recruitment:
(a) Direct Recruitment
(b) Causal callers
(c) Advertisement
(d) Employement Exchange
(e) Placement Agencies
(f) Campus recuitment
(g) Recommendation of Employees
(h) Labour Contractor
(i) Web Publishing
(j) Advertising on Television

2. What is meant by recruitment? How is it different from selection?

 Answer

Recruitment refers to the process of finding possible candidates for a job. It can be defined as the process of motivating and encouraging people to come and apply for a job in an organisation. Selection is the process of identifying and choosing the best person out of a number of prospective candidates for a job.
If recruitment is positive, selection is negative. Recruitment helps in creating a pool of prospective workforce whereas selection helps in finding the best out of them.

3. Define Training. How is it different from education?

 Answer

Training is any process by which the aptitudes, skills and abilities of employees to perform specific jobs are increased. It is a process of learning new skills and application of knowledge. In other word education is the process of increasing the knowledge and understanding of employees. It is the understanding and interpretation of knowledge.

Basis
Training
Education
PurposeImproves current job performance.Interpretation of knowledge and understanding.
ScopeNarrow (improve skills to do a particular job)Wider
Imparted byCompanies, firmsSchool, colleges

4. Distinguish between training and development.

Answer

Training
Development
It is a process of increasing knowledge and skills.It is a process of learning and growth.
It is to enable the employee to do the job better.It is to enable the overall growth of the employee.
It is a job oriented process.It is career oriented process.
Training is narrow in scope and focuses on how one can become more efficient in the intended job.Development is wider in scope and focuses on the overall personality development of the employee. Training is a part of development.

5. Why are internal sources of recruitment considered to be more economical?

Answer

Filling of jobs internally is cheaper as compared to getting candidates from external sources because only transfer or promotion has to be done. It does not involve the long process of staffing or selection. It increases the cost in the form of more time, money and efforts in recruiting, so internal sources of recruitment considered to be more economical.

6. What is the importance of staffing function in today’s environment?

Answer

Human resources are the foundation of any business because right people can help your business to the top and the wrong people can break whole business. So, the staffing function of management fills the requirement and finds the right people for the right job.
Proper staffing ensures the following benefits to the organisation:
•Helps in discovering and obtaining competent personnel for various jobs.
•Makes for higher performance, by putting right person on the right job.
•Ensures the continuous survival and growth of the enterprise through the succession planning for managers.
•Helps to ensure optimum utilisation of the human resources.
•Improves job satisfaction and morale of employees through objectives assessment and fair reward for their contribution.

Long Answer Type Questions

1. Define the staffing process and the various steps involved in it?

Answer

Staffing is that part of the process of management which is concerned with obtaining, utilising and maintaining a satisfactory and satisfied work force.

The following steps are involved in staffing process:

(i)  Estimating the Manpower Requirements - The first step in the staffing process is determining the present manpower inventory and assessing the present and future manpower requirements of the organisation keeping in mind the production schedule, demand etc.

(ii) Recruitment - Recruitment may be defined as the process of searching for prospective employees and stimulating them to apply for jobs in the organisation. For this various sources can be used like transfer, promotion, advertising, job consultants etc.

(iii) Selection - Selection is the process of choosing from among the pool of the prospective job candidates developed at the stage of recruitment. It involves a host of tests and interviews and select a right employee for a right job.

(iv) Placement and Orientation- The employee is given a brief presentation about the company and is introduced to his superiors, subordinates and the colleagues. orientation is, thus introducing the selected employee to other employees and familiarising him with rules and policies.

(v) Training and Development - All organisations have either in-house training centres or have forged alliances with training and educational institutes to ensure continued learning of their subordinates. By offering the opportunities for career advancement to their members, organisations are not only able to attract but also retain its talented staff.
Development refers to the learning opportunities designed to help employees grow. It covers not only those activities which improve job performance but also those which improve job performance but also those which bring about growth of the personality.

(vi) Performance Appraisal- It means evaluating an employee current and past performance as against certain predetermined standard.it include defining the job, appraising performance and providing feedback.

(vii) Promotion and Career Planning- It is a process through which filling higher job by promoting employees from lower jobs.it has great psychological impact over the employees because a promotion at higher level may lead to a chain of promotions at lower levels in the organisations and also gives a salary satisfaction. Managers need to design activities to serve employees long term interests. They must encourage their employees to grow and realise their full potential.

(viii) Compensation- All organisations need to establish wage and salary plans for their employees. There are various ways to prepare different pay plans depending on the worth of the job. Compensation therefore, refers to all forms of pay or rewards going to employees.

2. Explain the procedure for selection of employees.

Answer

The important steps in the process of selection are:

(i) Preliminary Screening - It helps the manager eliminate unqualified or unfit job seekers based on the information supplied in the application forms.

(ii) Selection Tests - An employment test is a mechanism that attempts to measure certain characteristics of individuals. These range from aptitudes, such as manual dexterity, to intelligence to personality. Some important test are Intelligence test, Aptitude test, Personality test, Trade test, Interest Test.

(iii) Employment Interview - Interview is a formal, in depth conversation conducted to evaluate the applicant’s suitability for the job.

(iv) Reference and Background Checks- Many employers request names, addresses and telephone numbers of references for the purpose of verifying information and gaining additional information on an applicant.

(v) Selection Decision -The final decision has to be made among the candidates who pass the tests, interviews and reference checks.

(vi) Medical Examination- Before the candidate is given a job offer he/she is required to go through a medical test. The job offer is given to the candidate being declared fit after the medical examination.

(vii) Job Offer- Job offer is made through a letter of appointment/confirm his acceptance. Such a letter generally contains a date by which the appointee must report on duty.

(viii) Contract of Employment-After the job offer has been made and candidate accepts the offer, certain documents need to be executed by the employer and the candidate. There is also a need for preparing a contract of employment. It includes job title, duties, responsibilities, date when continuous employment starts etc.

3. What are the advantages of training to the individual and to the organisation?

Answer

Training helps both the organisation and the individual.

Benefits to the Organisation:
(i) Training is a systematic learning which reduces the wastage of efforts and money.
(ii) Enhances employee productivity.
(iii) Training helps a manager to handle an emergency situation.
(iv) Training motivates workers and thus reduces absenteeism.
(v) Helps in adjusting to the changing environment (technological).

Benefits to the individual:
(i) Better career opportunities due to improved skills and knowledge.
(ii) Earnings can be increased due to improved performance.
(iii)Trained workers can handle machines more efficiently.
(iv) Employees always remain motivated and satisfied.

4. The staffing function is performed by every manager and not necessarily by a separate department. Explain.

Answer

Staffing is a function which all managers need to perform. It is a separate and specialised function and there are many aspects of human relations to be considered. It is the responsibility of all managers to directly deal and select people to work for the organisation. Nowadays, it is seen that organisations that are large in size, maintain a separate department for dealing with this function. This department is generally known as ‘Human Resource Department’. Under this department, the various tasks of staffing are performed by specialised managers. Along with staffing they also take care of the labour grievances. Human resource management thus act as a link between the workers and the managers.
However, staffing does not necessarily require a separate department and rather, is a function to be performed by every manager himself. Staffing forms an essential part of management. Managers here play an important role as they make sure about the optimum utilisation of the manpower. It is their task to watch if there is any vacancy and also, if any extra manpower is needed. Subsequently, they should work on how the recruitment has to be done, what qualifications are necessary for the applicants to apply for the job, and to what extent, training is necessary for that particular job. As managers are more closely related to the workers, they can work on the staffing process more efficiently. They can set the required qualifications for a particular job according to their need and work. For example, if a manager needs two subordinates to work under him then he’ll be able to mention the requirements more clearly. Similarly, they can perform the task of recruiting the personnel more smoothly as they would know what kind of personnel he would require and through what source he can gather an efficient pool of applicants, may it be internal or external sources, depending on his needs. As the main seekers of the employees, they can carry out the selection process of the right candidate in the best possible manner. Along with this, managers can also perform other important aspects of staffing namely, appraisal, promotions and career planning.
Thus, it can be said that staffing function is performed by every manager and not necessarily by a separate department.

Case study

1. A company X limited is setting up a new plant in India for – manufacturing auto components. India is a highly competitive and cost effective production base in this sector. Many reputed car manufacturers source their auto components from here. X limited is planning to capture about 40% of the market share in India and also export to the tune of at least $ 5 million in about 2 years of its planned operations. To achieve these targets it requires a highly trained and motivated work force. You have been retained by the company to advise it in this matter. While giving answer keep in mind the sector, the company is operating.

Answer

The prime concern of the company is to hire the manpower who are highly trained and motivated. In order to achieve the targets, the company should follow the staffing process in this manner

Estimating Manpower recruitment
Recruitment
Selection
Placement and orientation
Training and development

Because of rapid advancement of technology, increasing size of organisation and complicated behaviour of human beings, the ability of an organisation to achieve its goal depends upon the quality of its human resources.

2. Which sources of recruitment the company should rely upon? Give reasons for your recommendation.

Answer

The company is establishing a new unit in India. Thus, they should rely on external sources of recruitment. They should adopt this source and through employment exchange, placement agencies, labour contractors they will able to get the good staff in company.
This recommendation is fruitful because through these sources the company is having a wide choice of candidates, they can get the qualified personnel and brings new blood in the organisation who are highly competitive, will work harder to show better performance.

3. Outline the process of selection the company should follow with reasons.

Answer

The process of selection is:
Estimating Manpower recruitment
Recruitment
Selection
Placement and orientation
Training and development

Company should follow these steps in series as the first step preliminary screening helps the manager to select among those candidates whose applications are selected.
Second step is selection test it is to be conducted to check the practical knowledge of the candidate.
Third step interview is to be taken of those candidates who qualify the test. A panel of experts is called which are identifying the best among hundreds.
Fourth step is selection decision. The candidates who pass the test, interview included in selection list and critically examined that they are best or not.
Fifth step is examining their medical fitness they are efficient or not.
Sixth step is to offer the job, providing them a letter of appointment in which terms and conditions are mentioned.
The final step is contract of employment when candidate accepts the job offer they signed the contract of employment, the employer and candidate exchange certain documents.

4. Which methods of training and development should be company initiate? Explain giving reasons.

Answer

The company can use ‘On the job’ training methods or ‘off the training’ method
The merits or benefits of ‘On the job’ are:
Apprenticeship programmes:  These are designed to acquire a higher level of skill under the guidance of master worker.
Coaching: Through this method trainee works directly with a senior manager and the manager takes a full responsibility for the trainee coaching.

Internship training: It is a joint programme of training in which educational institutions and business firms cooperate.
If the ‘Off the job’ methods are used then the benefits derived are
(i) Vestibule training helps in avoiding modern and expensive equipments from being damaged.

(ii) Conference helps in to develop conceptual knowledge reduce, resistance to change etc.
Because it is more economical as compared to off the job training method, so company need to follow ‘off the job training’ method.

2. A major insurance company handled all recruiting screening and training processes for data entry/customer service representatives. Their competitor was attracting most of the, qualified, potential employees in their market. Recruiting was made even more difficult by the strong economy and the ‘job seeker’s market.’ This resulted in the client having to choose from candidates who had the ‘soft’ skills needed for the job, but lacked the proper ‘hard’ skills and training.

1. As an HR manager what problems do you see in the company?

Answer

 The human resource manager may face the following problems:-
(i) Lack of trained workforce.
(ii) Lack of sufficient personnel to provide customer services.
(iii) Inefficient maintenance of data.

2. How do you think it can be resolved?

Answer

Following steps can be taken to resolve these problems
(i) Proper training of the personnel.
(ii) Provision of incentive based schemes.
(iii) Proper data base should be maintained by the company in order to provide efficient services.

3. A public transport corporation has hired 1,000 buses for the different routes for the passengers of metropolitan city. Most of the 3,000 crewmen (drivers, conduct, helpers etc) of these buses have been found to be wanting in satisfactorily dealing with public and daily commuter. They seem to be little interested in the job and the job seem to have lost all meaning to them.

1. As manager of the public transport company what measures do you suggest to improve the working of crewman in question?

Answer

The following measures can be taken to improve the working of crewmen.

(i) Along with wages/salary various other facilities should be provided to them like education for their children, insurance etc.
(ii) Working hours should be between 7 to 8 per day.
(iii) Intervals should be provided.

2. Is it possible to modify their behaviour by planning a suitable type of training? Suggest one.

Answer

Yes, it is possible to modify their behaviour by planning ‘coaching’ training programme as in this programmes superior guides and instruct the trainee as a coach. He suggests the changes required in behaviour and performance of the employee. Coach gives due importance to the objective of individual and objectives of organisation.

4. Ms Jayshree recently completed her post graduate diploma in human resource management. A few months from now a large steel manufacturing company appointed her as its human resource manager. As of new, the company employs 800 persons and has an expansion plan in hand which may required another 200 persons for various types of additional requirements. Ms Jayshree has been given complete charge of the company’s human resource department.

1. Point out what functions is she supposed to perform?

Answer

Ms Jayshree as HR manager is required to perform the following functions
(i) Recruitment
(ii) Prepare job description
(iii) Preparing compensation and incentive plans
(iv) Arranging training programmes
(v) Making welfare schemes for employees
(vi) Handling grievances of employees
(vii) Handling labour dispute

2. What problems do you foresee in her job?

Answer

She may face the following problems:
(i) Properly qualified candidates may not be available.
(ii) Demand for wages may go higher.
(iii) After providing training the workers may leave the organisation.
(iv) Trade unions may bring unreasonable demands.

3. What steps is she going to take to perform her job efficiently?

Answer

Following steps can be taken by her to perform her job efficiently:
(i) She should make use of all the possible sources of recruitment.
(ii) She should frequently consult the experts and also observe the policies followed by competitors to recruit and retain the workforce.
(iii) Maintaining cordial relationship with trade unions and encouraging them to act as one big family.

4. How significant is her role in the organisation?

Answer

Her role is significant in the organisation. She is a human resources manager and concerned with timely procurement of competent manpower and ensuring its effective and efficient utilisation of manpower.
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R.D. Sharma Solutions Class 9th: Ch 24 Measure of Central Tendency Exercise 24.3

December 17, 2018, 9:15 pm
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Chapter 24 Measure of Central Tendency R.D. Sharma Solutions for Class 9th Exercise 24.3

Exercise 24.3

1. Find the median of the following data (1-8)
83, 37, 70, 29, 45, 63, 41, 70, 34, 54

Solution

The given data is 83, 37, 70, 29, 45, 63, 41, 70, 34 and 54.
Arranging the given data in ascending order, we have
29, 34, 37, 41, 45, 54, 63, 70, 70, 83
Here, the number of observation n = 10 , which is an even number.
Hence, the median is


2. 133, 73, 89, 108, 94, 104, 94, 85, 100, 120

Solution

The given data is 133, 73, 89, 108, 94, 104, 94, 85, 100 and 120.
Arranging the given data in ascending order, we have
73, 85, 89, 94, 94, 100, 104, 108, 120, 133
Here, the number of observation n = 10 , which is an even number.
Hence, the median is


3. 31, 38, 27, 28, 36, 25, 35, 40

Solution

The given data is 31, 38, 27, 28, 36, 25, 35 and 40.
Arranging the given data in ascending order, we have
25, 27, 28, 31, 35, 36, 38, 40
Here, the number of observation n = 10, which is an even number.
Hence, the median is

4. 15, 6, 16, 8, 22, 21, 9, 18, 25

Solution

The given data is 15, 6, 16, 8, 22, 21, 9, 18, and 25.
Arranging the given data in ascending order, we have
6, 8, 9, 15, 16, 18, 21, 22, 25
Here, the number of observation n = 9, which is an odd number.
Hence, the median is

5. 41, 43, 127, 99, 71, 92, 71, 58, 57

Solution

The given data is 41, 43, 127, 99, 71, 92, 71, 58 and 57.
Arranging the given data in ascending order, we have
41, 43, 57, 58, 71, 71, 92, 99, 127
Here, the number of observation n = 9, which is an odd number.
Hence, the median is


6. 25, 34, 31, 23, 22, 26, 35, 29, 20, 32

Solution

The given data is 25, 34, 31, 23, 22, 26, 35, 29, 20 and 32.
Arranging the given data in ascending order, we have
20, 22, 23, 25, 26, 29, 31, 32, 34, 35
Here, the number of observation n = 10, which is an even number.
Hence, the median is


7. 12, 17, 3, 14, 5, 8, 7, 15

Solution

The given data is 12, 17, 3, 14, 5, 8, 7 and 15.
Arranging the given data in ascending order, we have
3, 5, 7, 8, 12, 14, 15, 17
Here, the number of observation n = 8 , which is an even number.
Hence, the median is


8. 92, 35, 67, 85, 72, 81, 56, 51, 42, 69

 Solution

The given data is 92, 35, 67, 85, 72, 81, 56, 51, 42 and 69.
Arranging the given data in ascending order, we have
35, 42, 51, 56, 67, 69, 72, 81, 85, 92
Here, the number of observation n = 10, which is an even number.
Hence, the median is


9. Numbers 50, 42, 35, 2x + 10, 2x − 8, 12, 11, 8 are written in descending order and their median is 25, find x.

Solution

The given data in descending order is

50, 42, 35, 2x+10, 2x-8, 12, 11, 8
Here, the number of observation n = 8, which is an even number.
Hence, the median is


10. Find the median of the following observations: 46, 64, 87, 41, 58, 77, 35, 90, 55, 92, 33. If 92 is replaced by 99 and 41 by 43 in the above data, find the new median ?

 Solution

The given data is 46, 64, 87, 41, 58, 77, 35, 90, 55, 92 and 33.
Arranging the given data in ascending order, we have
33, 35, 41, 46, 55, 58, 64, 77, 87, 90, 92
Here, the number of observation n = 11, which is an odd number.
Hence, the median is

If 92 and 41 are replaced by 99 and 43 respectively, then the given data becomes 46, 64, 87, 43, 58, 77, 35, 90, 55, 99 and 33.
Arranging the new data in ascending order, we have
33, 35, 43, 46, 55, 58, 64, 77, 87, 90, 99
Here, the number of observation n = 11, which is an odd number.
Hence, the new median is


11. Find the median of the following data: 41, 43, 127, 99, 61, 92, 71, 58, 57 If 58 is replaced by 85, what will be the new median.

Solution

The given data is 41, 43, 127, 99, 61, 92, 71, 58 and 57.
Arranging the given data in ascending order, we have
41, 43, 57, 58, 61, 71, 92, 99, 127
Here, the number of observation n = 9 , which is an odd number.
Hence, the median is

If 58 is replaced by 85, then the given data become 41, 43, 127, 99, 61, 92, 71, 85 and 57.
Arranging the new data in ascending order, we have
41, 43, 57, 61, 71, 85, 92, 99, 127
Here, the number of observation n = 9, which is an odd number.
Hence, the new median is


12. The weights (in kg) of 15 students are : 31, 35, 27, 29, 32, 43, 37, 41, 34, 28, 36, 44, 45, 42, 30. Find the median. If the weight 44 kg is replaced by 46 kg and 27 kg by 25 kg, find the new median.

Solution

The weights (in kg) of 15 students are 31, 35, 27, 29, 32, 43, 37, 41, 34, 28, 36, 44, 45, 42 and 30.
Arranging them in ascending order, we have
27, 28, 29, 30, 31, 32, 34, 35, 36, 37, 41, 42, 43, 44, 45
Here, the number of observation n = 15, which is an odd number.
Hence, the median is

If the weights 44kg and 27kg are replaced by 46kg and 25kg respectively, then the given data becomes 31, 35, 25, 29, 32, 43, 37, 41, 34, 28, 36, 46, 45, 42 and 30.
Arranging the new data in ascending order, we have
25, 28, 29, 30, 31, 32, 34, 35, 36, 37, 41, 42, 43, 45, 46
Here, the number of observation n = 15, which is an odd number.
Hence, the new median is


13. The following observations have been arranged in ascending order. If the median of the data is 63, find the value of x:
23, 32, 48, 50, x, x+2, 72, 78, 84, 95

Solution

The given data in ascending order is
29, 32, 48, 50, x, x+2, 72, 78, 84, 95
Here, the number of observation n = 10, which is an even number.
Hence, the median is

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R.D. Sharma Solutions Class 9th: Ch 24 Measure of Central Tendency Exercise 24.4

December 18, 2018, 3:42 am
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Chapter 24 Measure of Central Tendency R.D. Sharma Solutions for Class 9th Exercise 24.4

Exercise 24.4

1. Find out the mode of the following marks obtained by 15 students in a class:
Marks: 4, 6, 5, 7, 9, 8, 10, 4, 7, 6, 5, 9, 8, 7, 7.

Solution

Given that the marks obtained by 15 students are 4, 6, 5, 7, 9, 8, 10, 4, 7, 6, 5, 9, 8, 7 and 7.
Make the following frequency table.

Since, the value 7 occurs maximum number of times, that is, 4. Hence, the mode value is 7.

2. Find the mode from the following data:
125, 175, 225, 125, 225, 175, 325, 125, 375, 225, 125

Solution

The given data is 125, 175, 225, 125, 225, 175, 325, 125, 375, 225, and 125.
Make the following frequency table.

Since, the value 125 occurs maximum number of times, that is, 4. Hence, the mode value is 125.

3. Find the mode for the following series:
7.5, 7.3, 7.2, 7.2, 7.4, 7.7, 7.7, 7.5, 7.3, 7.2, 7.6, 7.2

Solution

The given series is 7.5, 7.3, 7.2, 7.2, 7.4, 7.7, 7.7, 7.5, 7.3, 7.2, 7.6 and 7.2.
Make the following frequency table.

Since, the value 7.2 occurs maximum number of times, that is, 4. Hence, the modal value is 72.

4. Find the mode of the following data in each case:
(i) 14, 25, 14, 28, 18, 17, 18, 14, 23, 22, 14, 18
(ii) 7, 9, 12, 13, 7, 12, 15, 7, 12, 7, 25, 18, 7

Solution

(i) The given data is 14, 25, 14, 28, 18, 17, 18, 14, 23, 22, 14 and 18.
Make the following frequency table.

Here,14 occurs maximum number of times (that is 4). Hence, the modal value is 14.

(ii) The given data is 7, 9, 12, 13, 7, 12, 15, 7, 12, 7, 25, 18 and 7.
Make the following frequency table.

Since, the value 7 occurs maximum number of times, that is, 5. Hence, the modal value is 7.

5. The demand of different shirt sizes, as obtained by a survey, is given below:
Size:38394041424344Total
Number of persons (wearing it):263920151375125
Find the modal shirt sizes, as observed from the survey.

Solution

The demand of different shirt sizes is given as:

Here, x denotes the size of the shirts and f denotes the number of peoples (frequency) wearing it.
The value 39 occur maximum number of times, that is, 39. Hence, the modal shirt size is 39.
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