Class 11 Physics MCQs Thermodynamics for JEE/NEET

Here, you will get Class 11 Physics MCQ of Chapter 12 Thermodynamics for cracking JEE and NEET/AIIMS. By solving these MCQs of Class 11 Physics Chapter 12 Thermodynamics, you will get the confidence to crack JEE or NEET. Practice MCQ Questions for Class 11 Physics with Answers on a daily basis and score well in exams.

Thermodynamics Class 11 MCQs Questions with Answers

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

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

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

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

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

If the co-efficient of performance of a refrigerator is 5 and operates at the room temperature 27°C, the temperature inside the refrigerator is
(a) 250 K
(b) 230 K
(c) 260 K
(d) 240 K

Heat engine is a device by which a system is made to undergo a …X… process that result in conversion of …Y… into work. Here, X and Y refer to
(a) cyclic and heat
(b) None of these
(c) isothermal and heat
(d) cyclic and work

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

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

Air conditioner is based on the principle of
(a) refrigerator
(b) first law of thermodynamics
(c) None of these
(d) Carnot cycle

The bond energy (in kcal mol-1) of a C-C single bond is approximately
(a) 1
(b) 10
(c) 83-85
(d) 1000

In a system where Δ E = -51.0 kJ, a piston expanded against a pext of 1.2 atm giving a change in volume of 32.0 L. What was the change in heat of this system?
(a) -36 kJ
(b) -13 kJ
(c) -47 kJ
(d) 24 kJ

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

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

Answer: (d) second law of thermodynamics

Which of the following statements is correct for any thermodynamic system?
(a) The internal energy changes in all processes
(b) Internal energy and entropy are state functions
(c) The change in entropy can never be zero
(d) The work done in an adiabatic process is always zero

Answer: (b) Internal energy and entropy are state functions

In a heat reservoir, when a certain amount of heat is withdrawn from it, its temperature
(a) increases
(b) decreases
(c) remains constant
(d) becomes zero

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

The freezer in a refrigerator is located in the top section so that:
(a) motor is not heated
(b) heat gained from the environment is more
(c) heat gained from the environment is less
(d) the entire chamber of the refrigerator is cooled quickly

Answer: (d) the entire chamber of the refrigerator is cooled quickly

The efficiency of a Carnot engine working between 227°C and 27°C is
(a) 100%
(a) 50%
(c) 40%
(a) 20%

Tell which of the following phenomenon are reversible?
(a) Water fall
(b) Charging of a battery
(c) Rusting of iron by chemical change
(d) Production of heat by rubbing of hands

Answer: (b) Charging of a battery

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

The first law of thermodynamics is represented as
(a) dQ = dU + dW
(b) dQ = 2dU + dW
(c) dQ = dU – dW
(d) dQ = dU + 2dW

Answer: (a) dQ = dU + dW

Sometimes a cycle with well inflated tyres left in the Sun has its tube burst open. This is because the
(a) pressure of air inside the tube increases.
(b) volume of air inside the tube increases.
(c) both volume and pressure of air increases.
(d) none of the above.

Answer: (a) pressure of air inside the tube increases.

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