The refractive index of diamond is
[question] Question. The refractive index of diamond is 2.42. What is the meaning of this statement ? [/question] [solution] solution: We know that, absolute refractive index (n) of a medium is given by, $n=\frac{c}{v}$ or $v=\frac{c}{n}$ i.e., $v \propto \frac{1}{n}$ Since, the refractive index of diamond is 2.42, this suggests that the speed of light in diamond will reduce by a factor 2.42 compared to its speed in air. [/solution]...
Read More →Among the following, which country suffered disintegration due to political fights on the basis of religious and ethnic identities?
[question] Question. Among the following, which country suffered disintegration due to political fights on the basis of religious and ethnic identities? (a) Belgium (b) India (c) Yugoslavia (d) Netherlands [/question] [solution] Solution: (c) Yugoslavia [/solution]...
Read More →Arrange the following statements in a logical sequence and select the right answers by using the code given below.
[question] Question. Arrange the following statements in a logical sequence and select the right answers by using the code given below. Α. But all political expression of social divisions need not be always dangerous. B. Social divisions of one kind or the other exist in most countries. C. Parties try to win political support by appealing to social divisions. D. Some social differences may result in social divisions. (a) D, B, C, A (b) D, B, A, C (c) D, A, C, B (d) A, B, C, D [/question] [soluti...
Read More →You are given kerosene,
[question] Question. You are given kerosene, turpentine and water. Using the table given in question 3, find in which of these does the light travel fastest. [/question] [solution] solution: The light travels fastest in water as its refractive index is least $(v \propto 1 / n)$ among the three given substances. [/solution]...
Read More →Consider the following three statements.
[question] Question. Consider the following three statements. Α. Social divisions take place when social differences overlap. Β. It is possible that a person can have multiple identities. C. Social divisions exist in only big countries like India. Which of the statements is/are correct? (a) A, B and C (b) A and B (c) B and C (d) Only C [/question] [solution] Solution: (b) A and B [/solution]...
Read More →In dealing with social divisions which one of the following statements is NOT correct about democracy?
[question] Question. In dealing with social divisions which one of the following statements is NOT correct about democracy? (a) Due to political competition in a democracy, social divisions get reflected in politics. (b) In a democracy it is possible for communities to voice their grievances in a peaceful manner. (c) Democracy is the best way to accommodate social diversity. (d) Democracy always leads to disintegration of society on the basis of social divisions. [/question] [solution] Solution:...
Read More →From a rifle of mass 4 kg,
[question] Question. From a rifle of mass 4 kg, a bullet of mass 50 g is fired with a speed of 35 ms–1 Calculate the recoil speed of the rifle [question] [solution] Solution: Mass of rifle $=4 \mathrm{~kg}$ Let velocity of recoil of rifle $=\mathrm{v}$ Momentum of the rifle $=4 \times \mathrm{v}$ Mass of bullet $=50 \mathrm{~g}=\frac{50}{1000} \mathrm{~kg}=0.05 \mathrm{~kg}$ Velocity of bullet $=35 \mathrm{~ms}^{-1}$ Momentum of bullet $=0.05 \times 35$ Using the law of conservation of momentum,...
Read More →________________ social differences create possibilities of deep social divisions and tensions.
[question] Question. ________________ social differences create possibilities of deep social divisions and tensions. ________________ social differences do not usually lead to conflicts. [/question] [solution] Solution: Overlapping social differences create possibilities of deep social divisions and tensions. Cross cutting social differences do not usually lead to conflicts. [/solution]...
Read More →Find out, from Table given below,
[question] Question. Find out, from Table given below, the medium having highest optical density. Also find the medium with lowest optical density. [/question] [solution] solution: Among the media given in the above table, diamond has highest optical density as its refractive index is maximum among the given media. Air has least optical density as its refractive index is minimum among the given media. [/solution]...
Read More →How do social divisions affect politics? Give two examples.
[question] Question. How do social divisions affect politics? Give two examples. [/question] [solution] Solution: A combination of social divisions and politics can be really dangerous. A democracy involves competition among various political parties. As their competition tends to divide society, if they start competing in terms of some existing social divisions, then it can convert those social divisions into political divisions, which can lead to conflict, violence and even disintegration of t...
Read More →Explain, why is it difficult for a fireman to hold a hose pipe
[question] Question. Explain, why is it difficult for a fireman to hold a hose pipe which ejects large amounts of water at high velocity. [/question] [solution] Solution: We can explain the above observation on the basis of law of conservation of momentum. When the system of hose and water is not ejecting any water, its momentum is zero. When the water issues out from the hose with a high velocity, it has momentum in the forward direction. Therefore, in order to conserve momentum, the hose tends...
Read More →Light enters from air to glass having refractive index 1.50.
[question] Question. Light enters from air to glass having refractive index $1.50$. What is the speed of light in the glass ? The speed of light in vacuum is $3 \times 10^{8} \mathrm{~ms}^{-1}$. [/question] [solution] solution: We know that, absolute refractive index (n) of a medium is given by, $\mathrm{n}=\frac{\mathrm{c}}{\mathrm{v}}$ or $\mathrm{v}=\frac{\mathrm{c}}{\mathrm{n}}$ or $v_{\text {glass }}=\frac{c}{n_{\text {glass }}}=\frac{3 \times 10^{8}}{1.5}=2 \times 10^{8} \mathrm{~m} / \mat...
Read More →When does a social difference become a social division?
[question] Question. When does a social difference become a social division? [/question] [solution] Solution: When different social differences overlap, one particular social difference gains in prominence. This leads to the creation of social division and tension. For example, in Northern Ireland, the social differences of class and religion overlap each other. The catholics are usually the ones who are poor, while the protestants are the ones who are well off. The religious differences are acc...
Read More →If action is always equal to the reaction,
[question] Question. If action is always equal to the reaction, explain how a horse can pull a cart. [/question] [solution] Solution: When a horse pulls a cart with a certain force, then the cart pulls the horse with the same force and the system of horse and cart should not move. But, if we analyse the problem carefully, then horse not only applies force on the cart, but also pushes the earth backward with his feet. The earth reacts back to this action of the horse and pushes it in the forward ...
Read More →A ray of light travelling in air enters obliquely into water.
[question] Question. A ray of light travelling in air enters obliquely into water. Does the light ray bend towards the normal or away from the normal ? Why ? [/question] [solution] solution: The light ray bends towards the normal. This is because it enters from rarer (air) medium to denser (water) medium. [/solution]...
Read More →Discuss three factors that determine the outcomes of politics of social divisions
[question] Question. Discuss three factors that determine the outcomes of politics of social divisions. [/question] [solution] Solution: Three factors which determine the outcomes of politics of social divisions: The people’s perception of their identities When this is singular, the accommodation of other identities becomes difficult. Representation of a community by political leaders While representing a community, if politicians raise demands that are constitutional, then it is easier to accom...
Read More →Why do you fall in the forward direction when a moving bus applies brakes
[question] Question. Why do you fall in the forward direction when a moving bus applies brakes to stop and fall backward when it accelerates from rest ? [/question] [solution] Solution: When a moving bus applies brakes, our feet come to rest with the bus. But upper part of our body continues to move forward on account of inertia of motion. That is why we tend to fall in the forward direction. However, when the bus accelerates from rest, lower part of our body moves with the bus. The upper part o...
Read More →A concave mirror produces three times magnified
[question] Question. A concave mirror produces three times magnified (enlarged) real image of an object placed at 10 cm in front of it. Where is the image located? [/question] [solution] solution: Given, magnification, $m=-3$ (negative sign is taken as image is real); object distance $=-10 \mathrm{~cm}$ Now, $m=-\frac{v}{u} \quad$ or $\quad v=-m \times u$ or $\mathrm{v}=-(-3) \times(-10)=-30 \mathrm{~cm}$ [/solution]...
Read More →Explain why some of the leaves may get detached
[question] Question. Explain why some of the leaves may get detached from a tree if we vigorously shake its branch. [question] [solution] Solution: When we shake a branch of a tree vigorously, some of the leaves may get detached on account of inertia of rest of the leaves. The branch comes in motion and the leaves try to be in the position of rest. Therefore, they get detached. [solution]...
Read More →Find the focal length of a convex mirror
[question] Question. Find the focal length of a convex mirror whose radius of curvature is 32 cm. [/question] [solution] solution: Given, radius of curvature, $\mathrm{R}=+32 \mathrm{~cm}$ Focal length, $f=(1 / 2) \times$ radius of curvature or $\mathrm{f}=(1 / 2) \times \mathrm{R}=(1 / 2) \times(+32)=+16 \mathrm{~cm}$ [/solution]...
Read More →Consider the following statements.
[question] Question. Consider the following statements. A. In a federation the powers of the federal and provincial governments are clearly demarcated. B. India is a federation because the powers of the Union and State Governments are specified in the Constitution and they have exclusive jurisdiction on their respective subjects. C. Sri Lanka is a federation because the country is divided into provinces. D. India is no longer a federation because some powers of the states have been devolved to t...
Read More →Why do we prefer a convex mirror
[question] Question. Why do we prefer a convex mirror as a rear-view mirror in vehicles ? [/question] [solution] solution: Convex mirror is preferred as a rear-view mirror because it always gives an erect, though diminished image. Also, it has a wider field of view as it is curved outwards. Thus, convex mirror enables the driver to view much larger area than would be possible with a plane mirror. [/solution]...
Read More →In the following example, .
[question] Question. In the following example, try to identify the number of times the velocity of the ball changes. "A football player kicks a football to another player of his team who kicks the football towards the goal. The goalkeeper of the opposite team collects the football and kicks it towards a player of his own team". Also identify the agent supplying the force in each case. [question] [solution] Solution: The velocity of the football changes four times First time the velocity changes ...
Read More →Name a mirror that can give an erect
[question] Question. Name a mirror that can give an erect and enlarged image of an object. [/question] [solution] solution: Concave mirror [/solution]...
Read More →Match List I with List II and select the correct answer using the codes given below the lists:
[question] Question. Match List I with List II and select the correct answer using the codes given below the lists: [/question] [solution] Solution: [/solution]...
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