## Class 11 Physics Objective Chapter – 12 Thermodynamics

Here we are providing NCERT Class 11 Physics Objective Chapter – 12 Thermodynamics Chapter Wise MCQs for board exam is very important for board exam preparation. This book explains all the concepts and topics in very simple language that the students can easily understand the complex subjects also. This NCERT Class 11 Physics MCQs Chapter – 12 Thermodynamics Chapter consist all important topic regarding NCERT Class 11 Physics Objective Chapter – 12 Thermodynamics. This book basically covers all the major and minor elements that together form a democratic government. Topics like power-sharing, federalism, democracy and diversity, political parties, consequences of democracy, challenges to democracy etc. have been discussed in the NCERT Class 11 Physics Objective Chapter – 12 Thermodynamics. The question papers in CBSE board exams are generally based on the latest NCERT books. Hence, students must follow the NCERT book to prepare effectively for their Class 11 Physics exam. If you want color notes then click here

## Class 11 Physics Objective Chapter – 12 Thermodynamics

1. An engine has an efficiency of 1/6. When the temperature of sink is reduced by 62°C, its efficiency is doubled. Temperature of the source is:

( a ) 124°C

( b ) 37°C

( c ) 62°C

( d ) 99°C

Ans:-( d )

2. Internal energy of a perfect gas is

( a ) wholly potential energy

( b ) wholly kinetic energy

( c ) partially K.E. and partially P.E. of the molecules

( d ) difference of K.E. and P.E. of the molecules

Ans:-( a )

3.The branch of physics which deals with the concepts of heat and temperature and the inter conversion of heat and other forms of energy is called as

( a ) Statistical mechanics

( b ) Thermodynamics

( c ) Fluid dynamics

( d ) Classical physics

Ans:-( b )

4.The process forbidden by the first law of thermodynamics is

( a ) conversion of work into heat.

( b ) conversion of heat into work.

( c ) change in internal energy.

( d ) none of the above.

Ans:-( d )

5. A thermodynamical system is changed from state ( P1, V1 )to ( P2, V2 )by two different processes, the quantity which will remain same is:

( a ) ΔQ

( b ) ΔW

( c ) ΔQ + ΔW

( d ) ΔQ – ΔW

Ans:-( d )

6. A sample of 0.1 g of water at 100°C and normal pressure ( 1.013 × 105 N m–2 )requires 54 cal of heat energy to convert to steam at 100°C. If the volume of the steam produced is 167.1 cc, the change in internal energy of the sample, is

( a ) 104.3 J

( b ) 208.7 J

( c ) 42.2 J

( d ) 84.5 J

Ans:-( b )

7. First law of thermodynamics states that

( a ) heat is a form of energy

( b ) system has pressure

( c ) system has temperature

( d ) system can do work

Ans:-( a )

8.The Zeroth law leads to the concept of

( a ) temperature

( b ) heat

( c ) internal energy

( d ) work

Ans:-( a)

9. The temperatures of inside and outside of a refrigerator are 273 K and 303 K respectively. Assuming, that the refrigerator cycle is reversible, for every joule of work done, the heat delivered to the surrounding will be nearly:

( a ) 10 J

( b ) 20 J

( c ) 30 J

( d ) 50 J

Ans:-( c )

10.In an isothermal process, the internal energy of the system

( a ) decreases

( b ) increases

( c ) does not change

( d ) none of the above

Ans:-( c)

11. Thermodynamics is the ____ science

( a ) Microscopic

( b ) Macroscopic

( c ) Both a and b

( d ) None

Ans:-( b )

12. At a given volume and temperature, the pressure of a gas

( a ) varies inversely as its mass

( b ) varies inversely as the square of its mass

( c ) varies linearly as its mass

( d ) is independent of its mass

Ans:-( c )

13. A black body at a temperature of 227°C radiates heat at the rate of 20 cal m-2s-1. When its temperature rises to 727°C, the heat radiated will be

( a ) 40 units

( b ) 160 units

( c ) 320 units

( d ) 640 units

Ans:-( c )

14.The internal energy change in a system that has absorbed 2 kcal of heat and done 500 J of work is

( a ) 6400 J

( b ) 5400 J

( c ) 7900 J

( d ) 8900 J

Ans:-( c )

15. A system X is neither in thermal equilibrium with Y nor with Z. The systems Y and Z

( a ) may be in thermal equilibrium

( b ) None of these

( c ) cannot be in thermal equilibrium

( d ) must be in thermal equilibrium

Ans:-( a )

16. Which of the following is incorrect regarding the first law of thermodynamics? A. It is not applicable to any cyclic process B. It is a restatement of the principle of conservation of energy C. It introduces the concept of the internal energy D. It introduces the concept of the entropy

( a ) A and D

( b ) B and C

( c ) C and A

( d ) A and B

Ans:-( a)

17.Thermodynamics is concerned with the

( a ) change of state

( b ) measurement of heat

( c ) transfer of heat

( d ) none of the above

Ans:-( c)

18. Pressure, volume, temperature, mass are the

( a ) Microscopic variables

( b ) Macroscopic variables

( c ) Intensive variables

( d ) Extensive variables

Ans:-( b )

19. During an adiabatic process, the pressure of a gas is found to be proportional to the cube of its absolute temperature. The ratio Cp/Cv for the gas is

( a ) 2

( b ) 3/2

( c ) 4/3

( d ) 5/3

Ans:-( b )

20. In a thermodynamic process, pressure of a fixed mass of the gas is changed in such a manner that the gas molecules give out 30 J of heat. Also, 10 J of work is done on the gas. If the internal energy of the gas was 40 J, what will be the final internal energy?

( a ) 20 J

( b ) -20 J

( c ) 80 J

( d ) zero

Ans:-( a)

21.110 joule of heat is added to a gaseous system whose internal energy is 40 J, then the amount of external work done is

( a ) 150 J

( b ) 70 J

( c ) 110 J

( d ) 40 J

Ans:-( b )

22. Which of the following macroscopic variable is not measurable?

( a ) None of these

( b ) Volume

( c ) Pressure

( d ) Mass

Ans:-( a )

23.The translational kinetic energy of gas molecules at temperature T for one mole of a gas is

( a ) ( 3/2 )RT

( b ) ( 9/2 )RT

( c ) ( 1/3 )RT

( d ) ( 5/2 )RT

Ans:-( a)

( a ) temperature changes are bound to occur.

( b ) perfect thermal insulation with surroundings are required.

( c ) process should be quick.

( d ) all of the above are correct

Ans:-( d )

25. Two systems in thermal equilibrium with a third system separately are in thermal equilibrium with each other, this is the statement of

( a ) First law of thermodynamics

( b ) Second law of thermodynamics

( c ) Zeroth law of thermodynamics

( d ) None

Ans:-( c )

26.The temperature of a gas is due to the

( a ) K.E. of the gas molecules.

( b ) repulsive force between the molecules.

( c ) attractive force between the molecules.

( d ) P.E. of the gas molecules.

Ans:-( a)

27. Which of the following parameters dose not characterize the thermodynamic state of matter?

( a ) work

( b ) volume

( c ) pressure

( d ) Temperature

Ans:-( a )

28.First law of thermodynamics is consequence of conservation of

( a ) work

( b ) energy

( c ) heat

( d ) all of these

Ans:-( b )

29. Which of the following is a state variable ?

( a ) Internal energy

( b ) Heat

( c ) Work

( d ) All of these

Ans:-( a  )

30. A Carnots engine works as a refrigerator between 250 K and 300 K. If it receives 750 calories of heat from the reservoir at the lower temperature, the amount of heat rejected at the higher temperature is

( a ) 900 cal

( b ) 625 cal

( c ) 750 cal

( d ) 1000 cal

Ans:-( a )

31. For an isothermal expansion

( a ) process should be performed in very small steps.

( b ) perfect conducting communication with the surroundings is required.

( c ) process should be slow.

( d ) all of the above are correct.

Ans:-( d )

32.The SI unit of specific heat capacity is

( a )J kg-1 K

( b )J kg K

( c )J kg-1 K-1

( d )None

Ans:-( c)

33.The temperature of reservoir of Carnots engine operating with an efficiency of 70% is 1000 kelvin. The temperature of its sink is

( a ) 300 K

( b ) 400 K

( c ) 500 K

( d ) 700 K

Ans:-( a )

34.In a thermodynamic process, pressure of a fixed mass of the gas is changed in such a manner that the gas molecules give out 30 J of heat. Also, 10 J of work is done on the gas. If the internal energy of the gas was 40 J, what will be the final internal energy?

( a ) 20 J

( b ) −20 J

( c ) 80 J

( d ) zero

Ans:-( a )

35. If cp and cv denote the specific heats per unit mass of an ideal gas of molecular weight M, then

( a ) cp – cv = R/M2

( b ) cp – cv = R

( c ) cp – cv = R/M

( d ) cp – cv = MR

Ans:-( c )

36.The internal energy of an ideal gas depends upon

( a ) temperature

( b ) specific volume

( c ) pressure

( d ) density

Ans:-( a )

37.The temperatures of inside and outside of a refrigerator are 273 K and 303 K respectively. Assuming, that the refrigerator cycle is reversible, for every joule of work done, the heat delivered to the surrounding will be nearly

( a )10 J

( b )20 J

( c )30 J

( d )50 J

Ans:-( c )

38. In a Carnot’s engine, at the end point of the cycle, the temperature is

( a ) less than the initial temperature.

( b ) more than the initial temperature.

( c ) equal to the initial temperature.

( d ) zero.

Ans:-( c )

39.The amount of heat required to raise the temperature of 1g of water by 1°C is called as

( a )1 joule

( b )1 kJ

( c )One calorie

( d )None

Ans:-( c )

40. Heat cannot by itself flow from a body at lower temperature to a body at higher temperature is a statement as a conseqence of

( a ) conservation of mass

( b ) conservation of momentum

( c ) first law of thermodynamics

( d ) second law of thermodynamics

Ans:-( d )

41. A Carnot engine whose sink is at 300 K has an efficiency of 40%. By how much should the temperature of source be increased, so as to increase its efficiency by 50% of original efficiency?

( a ) 275 K

( b ) 325 K

( c ) 250 K

( d ) 380 K

Ans:-( c )

42. If the ratio of specific heat of a gas at constant pressure to that at constant volume is g, the change in internal energy of a mass of gas, when the volume changes from V to 2V at constant pressure P, is

( a ) PV /( γ – 1)

( b ) PV

( c ) R /( γ – 1)

( d ) γPV /( γ – 1)

Ans:-( a )

43.Energy transfer brought about by moving the piston of a cylinder containing the gas is known as

( a ) work

( b ) heat

( c ) pressure

( d ) temperature

Ans:-( a )

44.In a thermodynamic process, pressure of a fixed mass of the gas is changed in such a manner that the gas molecules give out 30 J of heat. Also, 10 J of work is done on the gas. If the internal energy of the gas was 40 J, what will be the final internal energy

( a ) 20 J

( b ) −20 J

( c ) 80 J

( d ) zero

Ans:-( a )

45. The first law of thermodynamics is represented as

( a ) dQ = dU + dW

( b ) dQ = 2dU + dW

( c ) dQ = dU – dW

( d ) dQ = dU + 2dW

Ans:-( a )

46. The variables which describes equilibrium states of system are called as

( a ) Intensive variables

( b ) Extensive variables

( c ) State variables

( d ) Thermodynamic state variables

Ans:-( d )

47. Which of the following is a state variable

( a ) Internal energy

( b ) Heat

( c ) Work

( d ) All of these

Ans:-( a )

48. For a diatomic gas change in internal energy for a unit change in temperature for constant pressure and constant volume is U1 and U2 respectively. What is the ratio of U1 and U2 ?

( a ) 5 : 3

( b ) 3 : 5

( c ) 1 : 1

( d ) 5 : 7

Ans:-( c )

49. One mole of an ideal gas requires 207 J heat to rise the temperature by 10 K when heated at constant pressure. If the same gas is heated at constant volume to raise the temperature by the same 10 K, the heat required is ( Given the gas constant R = 8.3 J/mole K )

( a ) 198.7 J

( b ) 29 J

( c ) 215.3 J

( d ) 124 J

Ans:-( d )

50. The state of a thermodynamic system is represented by

( a ) pressure, volume and temperature

( b ) volume only

( c ) pressure only

( d ) number of moles

Ans:-( a )

51.A Carnot engine whose sink is at 300 K has an efficiency of 40%. By how much should the temperature of source be increased, so as to increase its efficiency by 50% of original efficiency?

( a ) 275 K

( b ) 325 K

( c ) 250 K

( d ) 380 K

Ans:-( c)

52.The efficiency of a Carnot engine working between 227°C and 27°C is

( a ) 100%

( b ) 50%

( c ) 40%

( a ) 20%

Ans:-( c )