Multiple choice questions of Chapter 11 of Physics for First Year.

1. Heat is the form of:
a) Power
b) Work
c) Energy
d) Motion

2. Pressure of the gas depends upon: a) Only on molecular speed
b) Only on mass of molecule
c) Only on number of molecules in a unit volume
d) Number of molecules in a unit volume, mass and speed of molecule

3. In the isothermal process, one of the following is constant:
a) Pressure
b) Volume
c) Temperature
d) Heat energy
e) Specific heat

4. A process in which no heat enters or leaves the system is called:
a) Isothermal process
c) Isochoric process
d) Isobaric process

5. For a gas obeying Boyle’s law, if the pressure is doubled, the volume becomes:
a) Double
b) One half
c) Four times
d) One fourth

6. Gas law PVγ = constant is for:
a) Isothermal process
c) Isobaric process
d) Isochoric process

7. Cloud formation in the atmosphere is example of:
b) Isothermal process
c) Isochoric process
d) Isobaric process

8. Boyle’s law holds for ideal gases in.
a) Isochoric processes
b) Isobaric processes
c) Isothermal processes

9. Which one is true for internal energy?
a) It is sum of all forms of energies associated with molecules of a system.
b) It is a state function of a system
c) It is proportional to transnational K.E of the molecules
d) All are correct

10. The internal energy of an ideal gas is directly proportional to:
a) Potential energy
b) Translational kinetic energy
c) Vibrational kinetic energy
d) None of these

11. Which one is correct relation?
a) 𝐶𝑃 +𝐶𝑉 = 𝛾
b) 𝐶𝑃 = 1+𝑅/𝐶𝑉
c) 𝛾  = 𝐶𝑃/𝐶𝑉
d) 𝐶𝑃 = 1−𝑅/𝐶𝑉

12. Specific heats of a gas at constant pressure and at constant volume are respectively Cp and Cv :
a) Cp <  Cv
b) Cp >  Cv
c) Cp =  Cv
d) none of these

13. The first law of thermodynamics is an expression of:
a) The conservation of energy
b) Conservation of mass
c) Heat death of the universe

14. The amount of heat required raising the temperature of 1 kg of a substance through 1 K is called a) Specific heat
b) Heat capacity
c) Calorie
d) Joule

15. The expression for isothermal process is:
a) 𝑄 = 𝑈
b) 𝑄 = 𝑊
c) 𝑈 = 𝑊
d) 𝑈 = −𝑊

16. In adiabatic expansion, first law of thermodynamics becomes:
a) ∆𝑄 = ∆𝑊
b) ∆𝑄 = ∆𝑈
c) ∆𝑊 = ∆𝑈
d) None of these

17. The Celsius scale starts from:
a) 32°𝐹
b) 273 𝐾
c) 0°𝐶
d) 373 𝐾

18. Unit of thermodynamic scale of temperature is:
a) Kelvin
c) Fahrenheit
d) Celsius

19. Triple point of water is.
a) 373.16 𝐾
b) 284.16 𝐾
c) 300.16 𝐾
d) 273.16 𝐾

20. If the temperature of the sink is decreased, the efficiency of Carnot engine:
a) Decreases
b) Increases
c) Remains the same
d) First increases and then decreases

21. The area enclosed by the curve ABCDA for a Carnot heat engine represents the work done by Carnot engine.
a) At any instant
b) Averagely
c) During its operation
d) During one cycle

22. Carnot cycle is:
a) Reversible
b) Irreversible
c) Both
d) None of these

23. The efficiency of diesel engine is about:
a) 50%  𝑡𝑜  60%
b) 25%  𝑡𝑜  30%
c) 35%  𝑡𝑜  40%
d) 40%  𝑡𝑜  50%

24. The efficiency of petrol engine is about:
a) 30%  𝑡𝑜  35%
b) 25%  𝑡𝑜  30%
c) 35%  𝑡𝑜  40%
d) None of these

25. Working cycle of a typical petrol engine consists of:
a) Two strokes
b) Four strokes
c) Six strokes
d) Eight strokes

26. The increase in the entropy means the increase in:
a) Disorder
b) Unavailability of energy
c) Randomness
d) All of these

27. The property of a system that remains constant during an adiabatic process is called:
a) Internal energy
b) Entropy
c) Temperature
d) Pressure

28. In which process entropy remains constant.
a) Isobaric
b) Isochoric