Title 11. Thermal Properties Of Matter.pdf ✅

1. An ideal gas expand s in such a way that PV2 = constant throughout the process. (1) In the process, T-V diagram is a parabola (2) In the process, T-V diagram is a straight line (3) Such an expansion is possible only with heating (4) Such an expansion is possible only with cooling 2. A block of ice at –20°C having a mass of 2 kg is added to a 3 kg water at 15°C. Neglecting heat losses and the heat capacity of the container :- (1) The final temperature will be 0°C. (2) Ice will completely melt (3) Water will partially freeze (4) Final temperature will be more than 0°C 3. Two large holes are cut in a metal sheet. If this is heated, distances AB and BC, (as shown) (1) both will increase (2) both will decrease (3) AB increases, BC decreases (4) AB decreases, BC increases 4. If an electric heater is rated at 1000 W, then the time required to heat one litre of water from 20°C to 60°C is:- (1) 1 min 24 sec (2) 2 min 48 sec (3) 4 min 17 sec (4) 5 min 36 sec 5. A cylindrical metal rod of length L0 is shaped into a ring with a small gap as shown. On heating the system (1) x decreases, r and d increases (2) x and r increases, d decreases (3) x, r and d all increase (4) Data insufficient to arrive at a conclusion 6 . Work done in converting 1 g of ice at –10°C into steam at 100°C is– (1) 30 45 J (2) 6056 J (3) 725 J (4) 6 J 7. Six identical conducting rods are joined as shown in figure. Points A and D are maintained at temperatures 200°C and 20°C, respectively. the temperature of junction B will be :- (1) 12 0° C (2) 100°C (3) 140°C (4) 80°C 8. Hot water cools from 60°C to 50°C in the first 10 min and to 42°C in the next 10min. The temperature of the surrounding is– (1) 50°C (2) 10°C (3) 15°C (4) 20°C 9. A black body at a high temperature T K radiates energy at the rate E watt/m2 ; when the temperature falls to (T/2) K the radiated energy will be : (1) E/4 (2) E/2 (3) 2E (4) E/16 10. 200 g of a solid ball at 20°C is dropped in an equal amount of water at 80°C. The resulting temperature is 60°C. This means that specific heat of solid is : (1) One fourth of water (2) One half of water (3) Twice of water (4) Four times of water 11. If two rods of length L and 2L having coefficients of linear expansion  and 2 respectively are connected so that total length becomes 3L, the average coefficient of linear expansion of the composition rod equals: 1) 3 2  2) 5 2  3) 5 3  4) none of these 12. A flask containing air at 27°C at atmospheric pressure is corked up. A pressure of 2.5 atm would force the cork out. The temperature at which it happens is Thermal Properties of Matter
(1) 67.5° C (2) 750 K (3) 577° C (4) 670 K 13. Two rods of same length and area material transfer a given amount of heat in 12 seconds, when they are joined end to end. But when they are joined lengthwise, then they will transfer same heat in same conditions in : (1) 24 s (2) 3 s (3) 1.5 s (4) 48 s 14. An anisotropic material has coefficients of linear thermal expansion 1,2 and 3 along x, y and z-axis respectively. Coefficient of cubical expansion of this material will be equal to :- 15. The coefficient of apparent expansion of mercury in a glass vessel is 153 × 10–6 /°C and in a steel vessel is 144 × 10–6 / ° C. I f  for steel is 12 × 10–6 /°C, then  that of glass is : (1) 9 × 10–6 /°C (2) 6 × 10– 6 /°C (3) 36 × 10–6 /°C (4)27 × 10–6 /°C 16. A cylinder of radius R made of a material of thermal conductivity K1 is surrounded by a cylindrical shell of inner radius R and outer radius 2R made of material of thermal conductivity K2. The two ends of the combined system are maintained at two different temperatures. There is no loss of heat across the cylindrical surface and the system is in steady state. The effective thermal conductivity of the system is :- 17. A liquid takes 5 minutes to cool from 80°C to 50°C. How much time will it take to cool from 60°C to 30°C, if temperature of surroundings is 20° C : (1) 10 min (2) 12 min (3) 5 min (4) 9 min 18. 10 g of ice at 0°C is kept in a calorimeter of water equivalent 10 g. How much heat should be supplied to the system to evaporate the water :- { Lf = 80 cal/gm, L v = 540 cal/gm, Sw = 1 cal/gm} (1) 6200 cal (2) 7200 cal (3) 13600 cal (4) 8200 cal 19. A metal rod of length 2 m has cross sectional areas 2 A and A as shown in the adjacent figure. The ends of the rod are maintained at 100°C and 70°C. The temperature of middle point C is :- (1) 8°C (2) 85°C (3) 90°C (4) 95°C 20. A sol id sphere of copper of radius R and a hollow sphere of t he same material of inner radius r and outer radius R are heated to the same temperature and allowed to cool in the same environment. Hollow sphere : (1) will cool faster than solid sphere (2) will cool slower than solid sphere (3) will cool at the same rate as the solid sphere (4) data is not sufficient to decide 21 . 5kg of water at 10°C is added to 10kg of water at 40°C, the equilibrium temp. is close to (1) 25°C (2) 35°C (3) 33°C (4) 30°C 22. Three conducting rods of same material and cross-section are shown in figure. Temperatures of A, D and C are maintained at 20°C, 90°C and 0°C. The ratio of lengths of BD and BC if there is no heat flow in AB is :- (1) 2/7 (2) 7/2 (3) 9/2 (4) 2/9 23. A wall has two layers A and B, each made of a different material. Both the layers have the same thickness. The thermal
conductivity of the material of A is twice that of B. Under thermal equilibrium, the temperature difference across the wall is 36°C. The temperature difference across the layer A is :- (1) 6°C (2) 12°C (3) 18°C (4) 24°C 24. Steam at 100°C is passed into 22g of water at 20°C. The mass of water that will be present when the water acquires a temperature of 90°C (Latent heat of steam is 540 cal/g) is (1) 24.8 g (2) 24 g (3) 36.6 g (4) 30 g 25. The adjoining diagram shows the spectral energy density distribution E of a black body at two different temperatures. If the areas under the curves are in the ratio 16 : 1, the value of temperature T is (1) 32,000 K (2) 16,000 K (3) 8,000 K (4) 4,000 K 26. Solar radiation emitted by the sun resembles that emitted by a black body at a temperature of 6000 K. Maximum intensity is emitted at wavelength of about 4800 0 A . If the sun was cooled down from 6000 K to 3000 K, then the peak intensity would occur at a wavelength of :- (1) 4800 0 A (2) 9600 0 A (3) 2400 0 A (4) 19200 0 A 27. Suppose there is a hole in a copper plate. On heating the plate, diameter of hole, would : (1) always increase (2) always decrease (3) always remain the same (4) none of these 28. Two identical square rods of same metal are welded end to end as shown in figure (a). Assume that 10 cal of heat flows through the rods in 2 min. Now the rods are welded as shown in figure, (b). The time it would take for 10 cal to flow through the rods now, is (1) 0.75 min (2) 0.5 min (3) 1.5 min (4) 1 min 29. Two large holes are cut in a metal sheet. If this is heated, distances AB and BC, (as shown) (1) both will increase (2) both will decrease (3) AB increases, BC decreases (4) AB decreases, BC increases 30. On a new scale of temperature (which is linear) and called the W scale, the freezing and boiling points of water are 39°W and 239°W respectively. What will be the temperature on the new scale, corresponding to a temperature of 39°C on the Celsius scale :- (1) 200°W (2) 139°W (3) 78°W (4) 117°W 31. Two identical vessels A and B contain water at 30°C and 50°C respectively, so that the level of water in both are same. 10 cc of water is transferred from A to B. The water in B is mixed and 10 cc of it is transferred to A. Then (1) Level of water in both will remain same (2) Level of water in A will be more than that in B (3) Level of water in A will be less than that in B (4) Cannot be said from the given data 32. A copper block of mass 4 kg is heated in a furnace to a temperature 425°C and then placed on a large ice block. The mass of ice that will melt in this process will be: (Specific heat of copper = 500 J kg–1 °C–1 and heat of fusion of ice = 336 kJ kg–1 ) :- (1) 0.5 kg (2) 1 kg (3) 1.5 kg (4) 2.5 kg
33. A body cools from 50.0°C to 49.9°C in 5 s. How long will it take to cool from 40.0°C to 39.9°C? Assume the temperature of surroundings to be 30.0°C (1) 2.5 s (2) 10 s (3) 20 s (4) 5 s 34. A clock which keeps correct time at 20°C has a pendulum rod made of brass. How many seconds will it gain or lose per day when temperature falls to 0°C? ( ) 6 0  18 10 / C − =  :- (1) 155.5 s (2) 15.55 s (3) 25.55 s (4) 18.55 s 35. Two thermometers X and Y have ice points marked at 15° and 25° and steam points marked as 75° and 125° respectively. When thermometer X measures the temperature of a bath as 60° on it, what would thermometer Y read when it is used to measure the temperature of the same bath ? (1) 60° (2) 75° (3) 100° (4) 90° 36. The volume of a metal sphere increases by 0.15 % when its temperature is raised by 24°C.The coefficient of linear expansion of metal is : (1) 2.5×10–5 /°C (2) 2.0×10–5 /°C (3) –1.5×10–5 /°C (4) 1.2×10–5 /°C 37. Two solid sphere A and B made of the same material have radii rA and rB respectively. Both the spheres are cooled from the same temperature under to conditions valid for Newton's law of cooling. The ratio of the rate of change of temperature A and B is : (1) A B r r (2) B A r r (3) 2 2 A B r r (4) 2 2 B A r r 38. Assertion :- The star which is blue in colour emits more heat energy than the star which is red in colour. Reason :- Blue star is hotter than the red star. (1) A (2) B (3) C (4) D 39. Temperature of two stars are in ratio 3 : 2. If wavelength of maximum radiation from first body is 4000 0 A , What is corresponding wavelength of second body? (1) 9000 0 A (2) 6000 0 A (3) 2000 0 A (4) 8000 0 A 40. If the temperature of the sun was to increase from T to 2T and its radius from R to 2R, then the ratio of the radiant energy received on the earth to what it was previously will be :- (1) 4 (2) 16 (3) 32 (4) 64 41. Two circular discs A and B with equal radii and mass are blackened. They are heated to same temperature and are cooled under identical conditions. What inference do you draw from their cooling curves? (1) A and B have same specific heats (2) Specific heat of A is less (3) Specific heat of B is less (4) Nothing can be said 42. A sphere, a cube and a disc all of the same material, quality and volume are heated to 600oC and left in air. Which of these will have the lowest rate of cooling? (1) Sphere (2) Cube (3) Disc (4) All will have same rate 43. Two temperature scales A and B are released by 42 72 110 220 A B − − = . At which temperature two scales have the same reading? (1) –42o (2) –72o (3) +12o (4) –40o 44. A candle of diameter d is floating on a liquid in a cylindrical container of diameter D (D>>d) as shown in figure. It is burning at the rate of 4cm/hour, then the top of the candle will : (1) Remain at the same height (2) Fall at the rate of 2 cm / hour (3) Fall at the rate of 4 cm / hour (4) Go up at the rate of 2 cm / hour