Thermal Properties & Calorimetry PYQs Set 1 (PDF)

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Mere Teacher · Previous Year Questions NEET Physics · Thermal Properties & Calorimetry · Set 1 (Q1-30)
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1. $A cylindrical tod having temperature T_{1} and T_{2} at its ends. The rate of flow of heat is Q_{1} cells. If all the linear dimensional are doubled keeping temperature constant, then rate of flow of heat Q_{2} will be$ (1) $4 Q_{1}$ (2) $2 Q_{1}$ (3) $\frac{Q _{1}}{4}$ (4) $\frac{Q _{1}}{2}$ 2. $A cylinder with fixed capacity of 67.2 lit contains helium gas at STP . The amount of heat needed to raise the temperature of the gas by 20^{\circ} C is: Given that R = 8.31 J mol^{- 1} K^{- 1}]$ (1) $350 J$ (2) $374 J$ (3) $748 J$ (4) $700 J$ 3. $If a black body emits 0.5 joules of energy per second when it is at 27^{\circ} C, then the amount of energy emitted by it when it is at 627^{\circ} C will be$ (1) $13.5 J$ (2) $135 J$ (3) $40.5 J$ (4) $162 J$ 4. $A metal rod cools at the rate of 4^{\circ} C / min when its temperature is 90^{\circ} C and the rate of 1^{\circ} C / min when its temperature is 30^{\circ} C . The temperature of the surrounding is$ (1) $20^{\circ} C$ (2) $15^{\circ} C$ (3) $10^{\circ} C$ (4) $5^{\circ} C$ 5. $A cup of coffee cools from 90^{\circ} C to 80^{\circ} C in t minutes when the room temperature is 20^{\circ} C . The time taken by the similar cup of coffee to cool from 80^{\circ} C to 60^{\circ} C at the same room temperature is:$ (1) $\frac{13}{10} t$ (2) $\frac{10}{13} t$ (3) $\frac{5}{13} t$ (4) $\frac{13}{5} t$ 6. $Resistance of the wire is measured as 2 Ω and 3 Ω at 10°C and 30°C respectively. Temperature co-coefficient of resistance of the material of the wire is:$ (1) $0. 03 3^{0} C^{- l}$ (2) $-0. 033 3^{0} C^{- 1}$ (3) $0. 01 1^{0} C^{- 1}$ (4) $0.055° C^{- 1}$ 7. $A pendulum clock lose 12 s a day if the temperature is 40°C and gains 4 s a day if the temperature is 20°C. The temperature at which the clock will show correct time, and the co-efficient of linear expansion (α) of the metal of the pendulum shaft are respectively:$ (1) $60°C; α = 1.85 \times 1 0^{-4} /°C$ (2) $30°C; α = 1.85 \times 1 0^{-3} /°C$ (3) $55°C; α = 1.85 \times 1 0^{-2} /°C$ (4) $25°C; α = 1.85 \times 1 0^{-5} /°C$ 8. $A gun fires a lead bullet of temperature 300 K into a wooden block. The bullet having melting temperature of 600 K penetrates into the block and melts down. If the total heat required for the process is 625 J, then the mass of the bullet is grams. (Latent heat of fusion of lead = 2.5 \times 10^{4} JKg^{- 1} and specific heat capacity of lead = 125 JKg^{- 1} K^{- 1})$ (1) $10$ (2) $20$ (3) $5$ (4) $15$ 9. $Steam at 10 0^{0} C is passed into 20g of water at 1 0^{0} C When water acquires a temperature of 8 0^{0} C, the mass of water present will be: [ Take specific heat of water = 1 cal g^{-1}^{0} C^{-1} and latent heat of steam = 540 cal g^{-1}]$ (1) $24 g$ (2) $31.5 g$ (3) $42.5 g$ (4) $22.5 g$ 10. $An aluminium sphere of 20 cm diameter is heated from 0ºC to 100ºC. Its volume changes by (given that coefficient of linear expansion for aluminium α_{A I} = 23 \times 1 0^{-6} /ºC)$ (1) $2.89 cc$ (2) $9.28 cc$ (3) $49.8 cc$ (4) $28.9 cc$ 11. $A solid steel ball of diameter 3.6 mm acquired terminal velocity 2.45 \times 10^{- 2} m / s while falling under gravity through an oil of density 925 kg m^{- 3} . Take density of steel as 7825 kg m^{- 3} and g as 9.8 m / s^{2} . The viscosity of the oil in SI unit is$ (1) $2.18$ (2) $1.68$ (3) $2.38$ (4) $1.99$ 12. $The value of coefficient of volume expansion of glycerin is . The fractional change in the density of glycerin for a rise of in its temperature is$ (1) $0.015$ (2) $0.020$ (3) $0.025$ (4) $0.010$ 13. $Which of the following curves represent the variation of coefficient of volume expansion of an ideal gas at constant pressure?$ (1) (2) (3) (4) 14. $When heat Q is supplied to a diatomic gas of rigid molecules, at constant volume its temperature increases by ∆ T The heat required to produce the same change in temperature, at a constant pressure is:$ (1) $\frac{2}{3} Q$ (2) $\frac{5}{3} Q$ (3) $\frac{7}{5} Q$ (4) $\frac{3}{2} Q$ 15. $When 100 g of a liquid A at 100° C is added to 50 g of a liquid B at temperature 75° C, the temperature of the mixture becomes 90° C. The temperature of the mixture, if 100 g of liquid A at 100° C is added to 50 g of liquid B at 50° C, will be:$ (1) $85° C$ (2) $60° C$ (3) $80° C$ (4) $70° C$ 16. $A rigid diatomic ideal gas undergoes an adiabatic process at room temperature. The relation between temperature and volume for this process is TV^{x} = constant, then x is:$ (1) $\frac{3}{5}$ (2) $\frac{2}{5}$ (3) $\frac{2}{3}$ (4) $\frac{5}{3}$ 17. $A body cools from 80°C to 60° in 5 minutes. The temperature for the surrounding is 20°C. The time it takes to cool from 60°C to 40°C is$ (1) $450s$ (2) $420s$ (3) $500s$ (4) $\frac{25}{3} s$ 18. $The surface temperature of the stars is determined using$ (1) $Planck's law$ (2) $Wein's displacement law$ (3) $Rayleigh-Jeans law$ (4) $Kirchhoff's law.$ 19. $Due to cold weather a 1m water pipe of cross-sectional area 1 c m^{2} is filled with ice at - 1 0^{0} C. Resistive heating is used to melt the ice. Current 0.5A of is passed through 4 k Ω resistance. Assuming that all the heat produced is used for melting, what is the minimum time required? (Given latent heat of fusion for water/ice = 3.33 \times 1 0^{5} J k g^{- 1}, specific heat of ice = 2 \times 1 0^{3} J k g^{- 1} and density of ice = 1 0^{3} k g / m^{3})$ (1) $0.353s$ (2) $35.3s$ (3) $3.53s$ (4) $70.6s$ 20. $Ice at -20° C is added to 50g of water at 40° C, when the temperature of the mixture reaches 0° C, it is formed that 20 g of ice is still unmelted. The amount of ice added to the water was close to (Specific heat of water = 4.2 /J/g/°C Specific heat of ice = 4.2 /J/g/°C Heat of fusion of water at 0°C = 334J/g)$ (1) $50g$ (2) $100g$ (3) $60g$ (4) $40 g$ 21. $Ice at -20°C is added to 50 g of water at 40° C. When the temperature of the mixture reaches 0°C, it is found that 20 g of ice is still unmelted. The amount of ice added to the water was close to (Specific heat of water = 4.2J/g/°C Specific heat of Ice = 2.1 J/g/°C. Heat of fusion of water at 0°C = 334 J/g$ (1) $100 g$ (2) $40 g$ (3) $60 g$ (4) $50 g$ 22. $A diatomic gas with rigid molecules does 10 J of work when expanded at constant pressure. What would be the heat energy absorbed by the gas, in this process?$ (1) $25 J$ (2) $35 J$ (3) $30 J$ (4) $40 J$ 23. $On celcius scale the temperature of body increases by 40^{\circ} C . The increase in temperature on Fahrenheit scale is:$ (1) $68^{\circ} F$ (2) $75^{\circ} F$ (3) $72^{\circ} F$ (4) $70^{\circ} F$ 24. $A 3 m long wire of radius 3 mm shows an extension of 0.1 mm when loaded vertically by a mass of 50 kg in an experiment to determine Young's modulus. The value of Young's modulus of the wire as per this experiment is P \times 10^{11} Nm^{- 2}, where the value of P is: (Take g = 3 π m / s^{2})$ (1) $2.5$ (2) $25$ (3) $10$ (4) $5$ 25. $An ideal gas is expanding such that P T^{3} = constant. The coefficient of volume expansion of the gas is:$ (1) $\frac{1}{T}$ (2) $\frac{2}{T}$ (3) $\frac{4}{T}$ (4) $\frac{3}{T}$ 26. $A brass wire of length 2 m and radius 1 mm at 27^{\circ} C is held taut between two rigid supports. Initially it was cooled to a temperature of - 43^{\circ} C creating a tension T in the wire. The temperature to which the wire has to be cooled in order to increase the tension in it to 1.4 T, is____^{\circ} C .$ (1) $-86$ (2) $-65$ (3) $-71$ (4) $-80$ 27. $A lead bullet penetrates into a solid object and melts. Assuming that 40% of its kinetic energy is used to heat it, the initial speed of bullet is: Given, initial temperature of the bullet = 127°C, Melting point of the bullet = 327°C, Latent heat effusion of lead = 2.5 x 1 0^{4} J K g^{- 1}, Specific heat capacity of lead = 125J/kg K)$ (1) $125 m s^{- 1}$ (2) $500 m s^{- 1}$ (3) $250 m s^{- 1}$ (4) $600 m s^{- 1}$ 28. $Water is heated from 0^{\circ} C to 10^{\circ} C, then its volume$ (1) $increases$ (2) $first decreases and then increases$ (3) $decreases$ (4) $does not change.$ 29. $Two identical bodies are made of a material for which the heat capacity increases with temperature. One of these is at 100^{\circ} C, while the other one is at 0^{\circ} C . If the two bodies are brought into contact, then assuming no heat loss, the final common temperature is [NEET 2016]$ (1) $50^{\circ} C$ (2) $more than 50^{\circ} C$ (3) $less than 50^{\circ} C but greater than 0^{\circ} C$ (4) $0^{\circ} C$ 30. $An unknown metal of mass 192 g heated to a temperature of 100°C was immersed into a brass calorimeter of mass 128 g containing 240 g of water at a temperature of 8.4°C. Calculate the specific heat of the unknown metal if water temperature stabilizes at 21.5°C. (Specific heat of brass is 394 J k g^{-1} K^{-1})$ (1) $916 J k g^{-1} K^{-1}$ (2) $458 J k g^{-1} K^{-1}$ (3) $1232 J k g^{-1} K^{-1}$ (4) $654 J k g^{-1} K^{-1}$