Practice the Calorimetry Questions and Answers

Q1. 1 kg of ice at 0°C is mixed with 1 kg of steam at 100°C. What will be the composition of the system when thermal equilibrium is reached? Latent heat of fusion of ice = 3.36 × 105 J/kg and latent heat of vaporization of water 2.26 × 106 J/kg.

(a) 665 gm steam and 1.335 kg water
(b) 670 gm steam and 1.330 kg water
(c) 665 gm water and 1.335 kg steam
(d) 670 gm water and 1.330 kg steam

Q2. In the temperature range 100 – 1000 °C, the molar specific heat of a metal varies with temperature T (measured in degrees Celsius) according to the formula Cp = (1 + T/5) J-deg/C /mol .If 0.2 kg of the metal at 600 C is brought in thermal contact with 0.1 kg of the same metal at 300°C, the final equilibrium temperature, in deg C, will be

[Assume that no heat is lost due to radiation and/or other effects].

(a) 466
(b) 567
(c) 383
(d) 519

Q3. A bullet of mass 20 gm enters into a fixed wooden block with a speed of 40 m/s and stops in it. If all the energy converts into heat energy, then the heat energy produced is

(a) 16 J
(b) 32 J
(c) 8 J
(d) 64 J

Q4. A metal bullet comes to rest after hitting its target with a velocity of 80 m/s. If 50% of the heat generated remains in the bullet, what is the increase in its temperature? (The specific heat of the bullet 160 Joule per Kg per degree. C)

(a) 14° C
(b) 12.5° C
(c) 10° C
(d) 8.2° C

Q5. A heating element weighting 100 g made of a material with specific heat of 1J/(g.C) is exposed to ambient air at 30° C and attains a steady state temperature of 130° C while absorbing 100 W of electric power. Neglecting radiation, the time taken for the heating element to cool to 129° C after the power is switched off is most nearly equal to

(a) 0.01 second
(b) 0.1 second
(c) 1.0 second
(d) 10 second

Q6. A 50 kg man is running at a speed of 18 km/h . If all the kinetic energy of the man can be used to increase the temperature of water from 20°C  to 30°C how much water can be heated with this energy?

(a) 30 gm
(b) 75 gm
(c) 15 gm
(d) 45 gm

Q7. A block made of a metal with specific heat C resting on horizontals wooden board is imparted a speed v by an impulse. The metal block comes to rest due to friction with the wooden board (coefficient of kinetic friction ). If all the heat generated by friction absorbed by the metal block its temperature rises by

(a) μ2v2/2C
(b) {√(μ)v2}/2C
(c) v2/2C
(d) μv2/2C

Q8. A lead bullet penetrates into a solid object and melts. Assuming its 50% energy was used to heat it, calculate the initial speed of the bullet. The initial temperature of the bullet is 27°C and its melting point is 327°C. Latent heat of fusion of lead = 2.5 × 104 J/kg and specific heat capacity of lead = 125 J kg K

(a) 400 m/s
(b) 500 m/s
(c) 550 m/s
(d) 450 m/s

Q9. The heat capacity of a silver coin is 1.128 cal /°C, What should be its mass in gram? (Specific heat of silver = 0.0564 cal/g/°C)

(a) 100
(b) 50
(c) 20
(d) 70

Q10.An average person weighs 70 kg and produces 2500 kcal of heat per day. If humans were isolated system, what would be the temperature of this person after 24 hours? Assume that the initial temperature of the person was 37°C and the specific heat of the person is 1 cal/K/g.

(a) 37 °C
(b) 73 °C
(c) 67 °C
(d) 100 °C

Q11. A certain substance cools from 370 K to 330 K in 10 minutes. The temperature after 40 minutes will be

(a) 270 K
(b) 210 K
(c) 300 K
(d) 295 K

Q12. A Brass vessel feels much colder to the touch than a wooden vessel on a chilly day. Which of the following might explain this observation?

(a) Brass has a higher thermal conductivity than wood
(b) Brass has a higher specific heat capacity than wood
(c) The thermal conductivity of our hand depends on the material we touch
(d) Brass is heavier than wood

Q13. If ice contained in a beaker starts melting then

(a) the specific heat of the system is zero
(b) internal energy of the system remains constant
(c) entropy remains constant
(d) temperature remains constant

Q14. An aluminium vessel of ass 0.5 kg contains 0.2 kg of water at 20°C. A block of iron of mass 0.2 kg at 100°C is gently put into the water. Find the equilibrium temperature of the mixture. Specific heat capacities of aluminium iron and water are 910 J/kg/K, 470 J/kg/K, and 4200 J/kg/K respectively.

(a) 24.0 °C
(b) 24.4 °C
(c) 24.5 °C
(d) 25.0 °C

Q15. Beaker A has 100 ml of a fluid at 80°C and beaker B has 200 ml of the same fluid at 20°C. If both the fluids are mixed, what would be the resultant temperature of the mixture ?

(a) 20°C
(b) 80 °C
(c) 40 °C
(d) 50 °C

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