Thermal Properties & Calorimetry PYQs Set 2 (PDF)

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Set 2 of 5 · Questions 31-60 of 122

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Mere Teacher · Previous Year Questions NEET Physics · Thermal Properties & Calorimetry · Set 2 (Q31-60)
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31. $In a process, temperature and volume of one mole of an ideal monoatomic gas are varied according to the relation VT = K where K is a constant. In this process the temperature of the gas is increased by Δ T . The amount of heat absorbed by gas is (R is gas constant):$ (1) $\frac{1}{2} R Δ T$ (2) $\frac{1}{2} KR Δ T$ (3) $\frac{3}{2} R Δ T$ (4) $\frac{2 K}{3} Δ T$ 32. $Four rods with different radii r and length l are used to connect two heat reservoirs at different temperatures. Which one will conduct most heat?$ (1) $r = 1 cm, l = 1 m$ (2) $r = 1 cm, l = \frac{1}{2} m$ (3) $r = 2 cm, l = 2 m$ (4) $r = 2 cm, l = \frac{1}{2} m$ 33. $A copper block of mass 5.0 kg is heated to a temperature of 500°C and is placed on a large ice block. What is the maximum amount of ice that can melt? [Specific heat of copper: 0.39 J g^{- 1} ° C^{- 1} and latent heat of fusion of water: 335 J g^{- 1}]$ (1) $1.5 kg$ (2) $5.8 kg$ (3) $2.9 kg$ (4) $3.8 kg$ 34. $In a photoelectric experiment, the wavelength of the light incident on a metal is changed from 300 nm to 400 nm . The decrease in the stopping potential is close to: (\frac{hc}{e} = 1240 nm - V)$ (1) $0.5 V$ (2) $1.5 V$ (3) $1.0 V$ (4) $2.0 V$ 35. $The temperature of a body in air falls from 40^{\circ} C to 24^{\circ} C in 4 minutes. The temperature of the air is 16^{\circ} C . The temperature of the body in the next 4 minutes will be:$ (1) $\frac{14}{3}^{\circ} C$ (2) $\frac{42}{3}^{\circ} C$ (3) $\frac{28}{3}^{\circ} C$ (4) $\frac{56}{3}^{\circ} C$ 36. $Two rods A and B of identical dimensions are at temperature 30^{\circ} C . If A is heated upto 180^{\circ} C and B upto T^{\circ} C then the new lengths are the same. If the ratio of the coefficients of linear expansion of A and B is 4 : 3, then the value of T is:$ (1) $230^{\circ} C$ (2) $270^{\circ} C$ (3) $200^{\circ} C$ (4) $250^{\circ} C$ 37. $Which of the following best represents the temperature versus heat supplied graph for water, in the range of - 20^{\circ} C to 120^{\circ} C ?$ (1) (2) (3) (4) 38. $A pan filled with hot food cools form 94^{\circ} C to 86^{\circ} C in 2 minutes. When the room temperature is 20^{\circ} C . How long will it cool from 74^{\circ} C to 66^{\circ} C ?$ (1) $2 minutes$ (2) $2.8 minutes$ (3) $2.5 minutes$ (4) $1.8 minutes$ 39. $2 liters water at 27°C is heated by a 1 kW heater in an open container. On an average heat is lost to surroundings at the rate 160 J/s. The time required for the temperature to reach 77°C is$ (1) $8 min 20 sec$ (2) $10 min$ (3) $7 min$ (4) $14 min$ 40. $Time taken by a 836 W heater to heat one liter of water from 10ºC to 40ºC is:$ (1) $50 s$ (2) $100 s$ (3) $150 s$ (4) $200 s$ 41. $A copper rod of 88 cm and an aluminium rod of unknown length have their increase in length independent of increase in temperature. The length of aluminium rod is [NEET 2019]$ (1) $113.9 cm$ (2) $88 cm$ (3) $68 cm$ (4) $6.8 cm$ 42. $An aluminium and steel rods having same lengths and cross-sections are joined to make total length of 120 cm at 30^{\circ} C . The coefficient of linear expansion of aluminium and steel are 24 \times 10^{- 6} /^{\circ} C and 1.2 \times 10^{- 5} /^{\circ} C, respectively. The length of this composite rod when its temperature is raised to 100^{\circ} C, is____cm .$ (1) $120.20$ (2) $120.15$ (3) $120.06$ (4) $120.03$ 43. $A metal ball of mass 0.1 kg is heated upto 500° C and dropped into a vessel of heat capacity 800 J K^{- 1} and containing 0.5 kg water. The initial temperature of water and vessel is 30° C. What is the approximate percentage increment in the temperature of the water? [Specific Heat Capacities of water & metal are, respectively, 4200 Jk g^{- 1} K^{- 1} and 400 JK g^{- 1} K^{- 1}]$ (1) $15%$ (2) $30%$ (3) $25%$ (4) $20%$ 44. $Two conductors have the same resistances at 0^{\circ} C but their temperature coefficients of resistance are α_{1} and α_{2} The respective temperature coefficients for their series and parallel combinations are:$ (1) $α_{1} + α_{2}, \frac{α _{1} + α _{2}}{2}$ (2) $\frac{α _{1} + α _{2}}{2}, \frac{α _{1} + α _{2}}{2}$ (3) $α_{1} + α_{2}, \frac{α _{1} α _{2}}{α _{1} + α _{2}}$ (4) $\frac{α _{1} + α _{2}}{2}, α_{1} + α_{2}$ 45. $Liquid oxygen at 50K is heated to 300 K at constant pressure of 1 atm. The rate of heating is constant. Which one of the following graphs represents the variation of temperature with time$ (1) (2) (3) (4) 46. $The amount of heat energy radiated by a metal at temperature T is E . When the temperature is increased to 3 T, energy radiated is$ (1) $81 E$ (2) $9 E$ (3) $3 E$ (4) $27 E$ 47. $An external pressure P is applied on a cube at 0°C so that it is equally compressed from all sides. K is the bulk modulus of the material of the cube and α is its coefficient of linear expansion. Suppose we want to bring the cube to its original size by heating. The temperature should be raised by:$ (1) $3PKα$ (2) $\frac{P}{3 α K}$ (3) $\frac{P}{α K}$ (4) $\frac{3 α}{P K}$ 48. $At what temperature a gold ring of diameter 6.230 cm be heated so that it can be fitted on a wooden bangle of diameter 6.241 cm? Both the diameters have been measured at room temperature (27°C). (Given: coefficient of linear thermal expansion of gold α_{L} = 1.4 x 10-5 K^{- 1})$ (1) $125.7°C$ (2) $91.7°C$ (3) $425.7°$ (4) $152.7°C$ 49. $The quantities of heat required to raise the temperature of two solid copper spheres of radii r_{1} and r_{2} (r_{1} = 1.5 r_{2}) through 1 K are in the ratio [NEET 2020]$ (1) $\frac{9}{4}$ (2) $\frac{3}{2}$ (3) $\frac{5}{3}$ (4) $\frac{27}{8}$ 50. $Two cylindrical vessels of equal cross sectional area of 2 m^{2} contain water upto heights 10 m and 6 m, respectively. If the vessels are connected at their bottom then the work done by the force of gravity is (Density of water is 10^{3} kg / m^{3} and g = 10 m / s^{2})$ (1) $1 \times 10^{5} J$ (2) $4 \times 10^{4} J$ (3) $8 \times 10^{4} J$ (4) $6 \times 10^{4} J$ 51. $Two Carnot engines A and B are operated in series. The first one, A receives heat at T_{1} (= 600 K) and rejects to a reservoir at temperature T_{2} The second engine B receives heat rejected by the first engine and in turn, rejects to a heat reservoir at T_{3} (= 400 K) . Calculate the temperature T_{2} if the work outputs of the two engines are equal:$ (1) $600 K$ (2) $400 K$ (3) $300 K$ (4) $500 K$ 52. $On a temperature scale 'X' the boiling point of water is 65°X and the freezing point is -15°X. Assuming that the X scale is linear. The equivalent temperature corresponding to -95 °X on the Fahrenheit scale would be$ (1) $-112°F$ (2) $-48 °F$ (3) $-148 F$ (4) $-63°F$ 53. $A piece of ice falls from a height h, so that it melts completely. Only one-quarter of the heat produced is absorbed by the ice and all energy of ice gets converted into heat during its fall. The value of h is [Latent heat of ice is 3.4 \times 10^{5} J / kg and g = 10 N / kg] [NEET 2016]$ (1) $544 km$ (2) $136 km$ (3) $68 km$ (4) $34 km$ 54. $The sprinkling of water reduces slightly the temperature of a closed room because$ (1) $temperature of water is less than that of the room$ (2) $specific heat of water is high$ (3) $water has large latent heat of vaporization$ (4) $water is a bad conductor of heat.$ 55. $1 gram of ice is mixed with 1 gram of steam. At thermal equilibrium, the temperature of the mixture is$ (1) $100^{\circ} C$ (2) $55^{\circ} C$ (3) $0^{\circ} C$ (4) $50^{\circ} C$ 56. $A cup of tea cools from 65.5^{\circ} C to 62.5^{\circ} C in 1 minute in a room at 22.5^{\circ} C . How long will it take to cool from 46.5^{\circ} C to 40.5^{\circ} C in the same room?$ (1) $4 minutes$ (2) $2 minutes$ (3) $1 minute$ (4) $3 minutes$ 57. $1 kg of water at 100° C is converted into steam at 100° C by boiling at atmospheric pressure. The volume of water changes from 1.00 x 1 0^{- 3} m^{3} as a liquid to 1. 671 m^{3} as steam. The change in internal energy of the system during the process will be (Given latent heat of vaporisation = 2257 kJ / kg, Atmospheric pressure = 1 x 1 0^{5} Pa)$ (1) $-2426 kJ$ (2) $+2090 kJ$ (3) $-2090 kJ$ (4) $+2476 kJ$ 58. $The surface temperature of the sun which has maximum energy emission at 500 nm is 6000 K . The temperature of a star which has maximum energy emission at 400 nm will be$ (1) $8500 K$ (2) $4500 K$ (3) $7500 K$ (4) $6500 K .$ 59. $A sphere, a cube and a thin circular plate all of same material and same mass initially heated to same high temperature are allowed to cool down under similar conditions. Then the$ (1) $plate will cool the fastest and sphere the slowest$ (2) $cube will cool the fastest and plate the slowest$ (3) $plate will cool the fastest and cube the slowest$ (4) $sphere will cool the fastest and cube the slowest.$ 60. $A 100 g of iron nail is hit by a 1.5 kg hammer striking at a velocity of 60 m s^{- 1} . What will be the rise in the temperature of the nail if one fourth of energy of the hammer goes into heating the nail? [Specific heat capacity of iron = 0.42 J g^{- 1} ° C^{- 1}]$ (1) $675°C$ (2) $1600°C$ (3) $16.07°C$ (4) $6.75°C$