f Homogeneity of dimensions. (ii) Briefly explain the two drawbacks to use the period of simple pendulum as a time standard. (iii) Assess the total uncertainty in the final result of a timing experiment with the help of an example. (iv) Determine the dimensions of pressure and density. (v) Under what condition would a vector have components that are equal in magnitude. (vi) Justify the statement “A body cannot rotate about its centre of gravity under the action of its own weight”. (vii) If → → A . = 0, Can it be concluded that B → → A and B are perpendicular to each other? Support your answer with a proof. (viii) Why fog droplets appear to be suspended in air? (ix) Discuss the sign of acceleration due to gravity for a cricket ball thrown upward, for its upward and downward motion. (x) Can the velocity of an object reverse the direction when acceleration is constant? Justify with an example. (xi) It is advisable to fasten the seat belts during a fast drive. Why is it? (xii) Explain how would a bouncing ball behave in each of an elastic and inelastic collision with floor of room. 3. Write answers of any EIGHT questions. (8 x 2 = 16) (i) When a rocket enters the atmosphere, why does its nose cone become very hot? Where does this heat energy come from? (ii) State the work energy principle. Express it in equation. (iii) While calculating the Absolute Gravitational potential energy, why is the distance between infinity and surface of earth is divided into very small steps. (iv) What is meant by moment of Inertia? Give its significance. (v) How is artificial gravity created in an Artificial satellites. (vi) Centripetal force and centrifugal reaction are equal in magnitude but opposite in direction. Why these forces do not balance each other. (vii) What happens to the period of simple pendulum if (a) its length is doubled (b) its suspended mass is doubled. (viii) Show that in SHM, the acceleration is zero when velocity is greatest and the velocity is zero when the acceleration is greatest? (ix) Why can we not realize an Ideal simple pendulum. (x) What features do longitudinal waves have in common with transverse waves. (xi) Why does sound travel faster in solids than in gases? (xii) Justify the statement “Velocity of sound in a gas is independent of pressure of the gas” 4. Write answers of any SIX questions. (6 x 2 = 12) (i) Define coherent sources of light. How two light beams can be made coherent. (ii) How is the distance between interference fringes is affected by the separation between the slits of Young’s double shit experiment? (iii) How would you distinguish between unpolarized light and plane polarized light. (iv) Name and explain any two of major components of a fiber optic communication system. (v) How the resolving power of a compound microscope can be increased. (vi) What happens to the temperature of the room, when an air conditioner is left running on a table in the middle of the room. (vii) What is meant by tripple point of water. What is the value of Absolute temperature of tripple point of water. (viii) Can the efficiency of a carnot engine be 100%? Justify your answer with proof. (ix) Normal Human body temperature is F 0 98 . Convert it into 6. 0 C and K. P.T.O
Posted on: Thu, 13 Jun 2013 04:40:20 +0000
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