## Wednesday, March 9, 2011

### Class XI Physics Revision Tests - Thermodynamics

PHYSICS TEST PAPER

THERMODYNAMICS

Max marks 35

Time 1 ½ hrs

Questions 1 to 5: 1 mark  each

Questions 6 to 10: 2 marks each

Questions 11 to 15: 3 marks each

Question 16: 5 marks

1. What is an isochoric process?

2. On what factors does the efficiency of a Carnot engine depend?

3. State second law of thermodynamics. (Any one statement)

4. State zeroth law of thermodynamics.

5. What is a heat engine?

6. State first law of thermodynamics and apply it to an isothermal process.

7. Explain why a balloon is cooler after it bursts.

8. What is a PV diagram? What does the area between the PV curve and the volume axis signify?

9. State the conditions for two bodies to be in thermal equilibrium.

10. State Carnot’s theorem and explain its significance.

11. What is a cyclic process? Show that the work done in a cyclic process is equal to the area enclosed by the loop representing the cyclic process.

12. Why gases have two principal specific heat capacities? Define them

13. Why Cp > Cv? Prove that Cp - Cv = R

14. Define the coefficient of performance of a heat pump. (refrigerator) and obtain a relation for it in terms of temperature T1 and T2

15. A sample of gas (γ = 1.5) is compressed adiabatically from a volume of 1600 cm3 to 400 cm3.  If the initial pressure is 150 kPa, what is the final pressure and how much work is done on the gas in the process?

16. Explain the construction and various operations involved in a Carnot’s heat engine with neat labeled diagram. Draw Carnot’s cycle and write expression for efficiency of a Carnot’s heat engine.

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