KKMishra's Tutorials: H C Verma solutions, Laws of Thermodynamics, OBJECTIVE-II, Chapter-26, Concepts of Physics, Part-II

Laws of Thermodynamics

OBJECTIVE-II

1. The pressure p and volume V of an ideal gas both increase in a process.

(a) Such a process is not possible.

(b) the work done by the system is positive.

(c) The temperature of the system must increase.

(d) Heat supplied to the gas is equal to the change in internal energy.

Answer: (b), (c).

EXPLANATION: Such a process is possible. The work done by the system is pressure x change in volume.

W = ∫p*dV

Here the volume is increasing, hence the work is done by the system. Option (b) is true.

For an ideal gas, pV = nRT

→T = pV/nR

Since p and V both increases, T will also increase. Option (c) is true.

Since the work done by the system is not zero, statement (d) is not true.

2. In a process on a system, the initial pressure and volume are equal to the final pressure and volume.

(a) The initial temperature must be equal to the final temperature.

(b) The initial internal energy must be equal to the final internal energy.

(c) The net heat given to the system in the process must be zero.

(d) The work done by the system in the process must be zero.

Answer: (a), (b).

EXPLANATION: For an ideal gas,

T =pV/nR

Since the value of pV is the same for the initial and final points, T will also be the same. Hence the option (a) is true.

At a constant volume, the internal energy is proportional to the temperature. Since the initial and final temperatures are the same, internal energy is also the same. Option (b) is true.

It may be possible that net heat is given to the system and an equal amount of work is done by the system. Hence the options (c) and (d) are not true.

3. A system can be taken from the initial state p₁, V₁ to the final state p₂, V₂ by two different methods. Let ΔQ and ΔW represent the heat given to the system and the work done by the system. Which of the following must be the same in both methods?

(a) ΔQ

(b) ΔW

(c) ΔQ+ΔW

(d) ΔQ-ΔW.

Answer: (d)

EXPLANATION: The heat given ΔQ to the system and the work done ΔW by the system depends upon the path followed by the process, hence the options (a), (b) and (c) are not true.

The internal energy of a system is a state function. Hence in both the processes the initial and the final internal energies will be the same and hence the change in the internal energy ΔU will be the same. From the first law of the thermodynamics,

ΔQ = ΔU + ΔW

→ΔU = ΔQ - ΔW will be the same in both processes. Option (d) is true.

4. Refer to the figure (26-Q5). Let ΔU₁ and ΔU₂ be the change in internal energy in processes A and B respectively, ΔQ be the net heat given to the system in process A+B and ΔW be the net work done by the system in the process A+B.

The figure for Q-4

(a) ΔU₁+ΔU₂ = 0.

(b) ΔU₁-ΔU₂ = 0.

(c) ΔQ-ΔW = 0.

(d) ΔQ+ΔW = 0.

Answer: (a), (c).

EXPLANATION: The process A+B is a cyclic process. Hence the system comes to the initial state A and the change in the internal energy ΔU = 0. Thus

ΔU =ΔU₁+ΔU₂ =0.

Option (a) is true.

And option (b) is not true.

From the first law of thermodynamics, ΔU =ΔQ-ΔW. Since ΔU = 0 in the process A+B, hence ΔQ-ΔW = 0. Option (c) is true.

5. The internal energy of an ideal gas decreases by the same amount as the work done by the system.

(a) The process must be adiabatic.

(b) The process must be isothermal.

(c) The process must be isobaric.

(d) The temperature must decrease.

Answer: (a), (d).

EXPLANATION: From the first law of thermodynamics,

ΔQ =ΔU +ΔW

Given that, ΔW = -ΔU, hence,

ΔQ = 0. So the heat exchanged to the system is zero, and the process is adiabatic, not isothermal. Option (a) is correct.

The process can not be isobaric, because in this process pressure is constant and the work is done due to the heat energy given. Since (a) is true there will not be heat transfer.

Since the internal energy decreases, the temperature in this adiabatic process must decrease. Option (d) is true.

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Links to the Chapters

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CHAPTER- 26-Laws of Thermodynamics

Questions for Short Answer

OBJECTIVE - I

CHAPTER- 25-CALORIMETRY

Questions for Short Answer

OBJECTIVE-I

OBJECTIVE-II

EXERCISES - Q1 to Q10

EXERCISES - Q-11 to Q-18

CHAPTER- 24-Kinetic Theory of Gases

Questions for Short Answer

OBJECTIVE - I

OBJECTIVE - II

EXERCISES- Q1 to 10

EXERCISES- Q11 to 20

EXERCISES- Q21 to 30

EXERCISES- Q31 to Q40

EXERCISES- Q41 to Q50

EXERCISES- Q51 to Q62

CHAPTER- 23 - Heat and Temperature

Questions for Short Answer

OBJECTIVE - I

OBJECTIVE - II

EXERCISES - Q-1 TO Q-10

EXERCISES - Q-11 TO Q-20

EXERCISES - Q-21 TO Q-34

CHAPTER- 22 - Photometry

Questions for Short Answer

OBJECTIVE - I

OBJECTIVE - II

EXERCISES

CHAPTER- 21 - Speed of Light

Questions for Short Answers

OBJECTIVE-I

OBJECTIVE-II

EXERCISES

CHAPTER- 20 - Dispersion and Spectra

Questions for Short Answers

OBJECTIVE-I

OBJECTIVE-II

EXERCISES

CHAPTER- 19 - Optical Instruments

Questions for Short Answers

OBJECTIVE-I

OBJECTIVE-II

EXERCISES - Q 1 to Q 12

EXERCISES - Q 13 to Q 24

CHAPTER- 18 - Geometrical Optics

Questions for Short Answers

OBJECTIVE-I

OBJECTIVE-II

EXERCISES - Q 1 to Q10

EXERCISES- Q11 to Q20

EXERCISES- Q21 to Q30

EXERCISES- Q31 to Q40

EXERCISES- Q41 to Q50

EXERCISES- Q51 to Q60

EXERCISES- Q61 to Q70

EXERCISES- Q71 TO 79

CHAPTER- 17 - Light Waves

Questions for Short Answers

OBJECTIVE - I

OBJECTIVE - II

EXERCISES - Q1-Q10

EXERCISES - Q11-Q20

EXERCISES - Q21-Q30

EXERCISES - Q31-Q41

CHAPTER- 16 - Sound Waves

Questions for Short Answers

OBJECTIVE-I

OBJECTIVE-II

EXERCISES - Q-1 TO Q-10

EXERCISES - Q-11 TO Q-20

EXERCISES -Q-21 TO Q-30

EXERCISES -Q-31 TO Q-40

EXERCISES -Q-41 TO Q-50

EXERCISES -Q-51 TO Q-60

EXERCISES -Q-61 TO Q-70

EXERCISES - Q-71 TO Q-80

EXERCISES - Q-81 TO Q-89

CHAPTER- 15 - Wave Motion and Waves on a String

Questions for Short Answers

OBJECTIVE-I

OBJECTIVE-II

EXERCISES - Q-1 TO Q-10

EXERCISES - Q-11 TO Q-20

EXERCISES - Q-21 TO Q-30

EXERCISES - Q-31 TO Q-40

EXERCISES - Q-41 TO Q-50

EXERCISES - Q-51 TO Q-57

CHAPTER- 14 - Fluid Mechanics

Questions for Short Answers

OBJECTIVE-I

OBJECTIVE-II

EXERCISES- Q-1 TO Q-10

EXERCISES- Q-11 TO Q-20

EXERCISES- Q-21 TO Q-32

CHAPTER- 13 - Fluid Mechanics

Questions for Short Answers

OBJECTIVE-I

OBJECTIVE-II

EXERCISES Q-1 TO Q-10

EXERCISES- Q11 TO Q20

EXERCISES Q-21 TO Q30

EXERCISES Q-31 TO Q35

CHAPTER- 12 - Simple Harmonic Motion

Questions for Short Answers

OBJECTIVE-I

OBJECTIVE-II

EXERCISES- Q1 TO Q10

EXERCISES- Q11 TO Q20

EXERCISES- Q21 TO Q30

EXERCISES- Q31 TO Q40

EXERCISES- Q41 TO Q50

EXERCISES- Q51 TO Q58 (2-Extra Questions)

CHAPTER- 11 - Gravitation

Questions for Short Answers

OBJECTIVE - I

OBJECTIVE - II

EXERCISES - Q_1 to Q_10

EXERCISES -Q-11 TO Q-20

EXERCISES -Q 21 TO 30

EXERCISES -Q 31 TO 39

CHAPTER- 10 - Rotational Mechanics

Questions for Short Answers

OBJECTIVE - I

OBJECTIVE - II

EXERCISES - Q-1 TO Q-15

EXERCISES - Q-16 TO Q-30

EXERCISES Q-31 TO Q-45

EXERCISES Q-46 TO Q-60

EXERCISES Q-61 TO Q-75

EXERCISES Q-76 TO Q-86

CHAPTER- 9 - Center of Mass, Linear Momentum, Collision

Questions for Short Answers

Objective - I

Objective - II

EXERCISES Q-1 TO Q-10

EXERCISES Q-11TO Q-20

EXERCISES Q-21 TO Q-30

EXERCISES Q-31 TO Q-42

EXERCISES Q-43 TO Q-54

CHAPTER- 8 - Work and Energy

Click here for → Question for Short Answers

Click here for → OBJECTIVE-I

Click here for → OBJECTIVE-II

Click here for → Exercises (1-10)

Click here for → Exercises (11-20)

Click here for → Exercises (21-30)

Click here for → Exercises (31-42)

Click here for → Exercise(43-54)

CHAPTER- 7 - Circular Motion

Click here for → Questions for Short Answer

Click here for → OBJECTIVE-I

Click here for → OBJECTIVE-II

Click here for → EXERCISES (1-10)

Click here for → EXERCISES (11-20)

Click here for → EXERCISES (21-30)

CHAPTER- 6 - Friction

Click here for → Questions for Short Answer

Click here for → OBJECTIVE-I

Click here for → Friction - OBJECTIVE-II

Click here for → EXERCISES (1-10)

Click here for → Exercises (11-20)

Click here for → EXERCISES (21-31)

For more practice on problems on friction solve these- "New Questions on Friction".

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CHAPTER- 5 - Newton's Laws of Motion

Click here for → QUESTIONS FOR SHORT ANSWER

Click here for→ Newton's laws of motion - Objective - I

Click here for → Newton's Laws of Motion - Objective -II

Click here for → Newton's Laws of Motion-Exercises(Q. No. 1 to 12)

Click here for→Newton's Laws of Motion,Exercises(Q.No. 13 to 27)

Click here for→Newton's Laws of Motion,Exercises(Q.No. 28 to 42)

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CHAPTER- 4 - The Forces

The Forces-

"Questions for short Answers"

Click here for "The Forces" - OBJECTIVE-I

Click here for "The Forces" - OBJECTIVE-II

Click here for "The Forces" - Exercises

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Wednesday, February 5, 2020

H C Verma solutions, Laws of Thermodynamics, OBJECTIVE-II, Chapter-26, Concepts of Physics, Part-II