Thermodynamics VBQs Class 11 Physics

VBQs for Class 11

VBQs Thermodynamics Class 11 Physics with solutions has been provided below for standard students. We have provided chapter wise VBQ for Class 11 Physics with solutions. The following Thermodynamics Class 11 Physics value based questions with answers will come in your exams. Students should understand the concepts and learn the solved cased based VBQs provided below. This will help you to get better marks in class 11 examinations.

Thermodynamics VBQs Class 11 Physics

Question. P-T diagram for an ideal gas undergoing a change ABC is as shown in figure. Corresponding V-T graph will be  

Answer

B

Question. Workdone by the ideal gas during the process AB is 

(a) 15 J
(b) 30 J
(c) 10 J
(d) 25 J

Answer

A

Question. Efficiency of heat engine is 0.5 when its sink temperature is 500 K. If the sink temperature is made 400 K at same source temperature, then the efficiency becomes / remains
(a) 0.5
(b) 0.4
(c) 0.6
(d) 0.8

Answer

C

Question. In the diagram shown below some thermodynamic processes are drawn. Which one is an isothermal process?  

(a) aa′
(b) bb′
(c) cc′
(d) All of these

Answer

C

Question. An ideal gas expands isothermally from a volume V1 to V2 and then compressed to original volume V1 adiabatically. Initial pressure is P1 and final pressure
is P3. The total work done is W. Then
(a) P3 > P1 , w > 0
(b) P3 < P1 , w < 0
(c) P3 > P1 , w < 0
(d) P3 = P1 , w = 0

Answer

C

Question. One mole of an ideal gas at a temperature T1K expands slowly according to the law P/V constant .
The final temperature is T2K. The work done by the gas is
(a) R (T2–T1)
(b) 2R (T2–T1)
(c) R/2 (T2–T1)
(d) 2R/3 (T2–T1)

Answer

C

Question. A sample of gas follows process AB, then which of the following is incorrect about AB? 

(a) ΔU = 0
(b) W > 0
(c) Q = W
(d) ΔU < 0

Answer

D

Question. The processes 1 and 2 enclose a circular area. An ideal gas is changing from A to B through process 1 absorbs 5π J. Heat absorbed by the same gas changing from A to B through process 2 is   

(a) 2.5π J
(b) Zero
(c) 5π
(d) 7.5π

Answer

A

Question. If a graph is plotted between pressure (P) and temperature (tºC) for an ideal gas at constant volume, then the nature of the graph is  

Answer

C

Question. Change in internal energy of the gas during the process ABC is 20 J. Change in internal energy in the process CA will be 

(a) –20 J
(b) –10 J
(c) 20 J
(d) 25 J

Answer

A

Question. In which of the following processes work done is more?  

(a) A
(b) B
(c) C
(d) D

Answer

A

Question. An ideal gas, (γ = 5/3) is changed from initial state (100 kPa, 100 cc) to (200 kPa, 200 cc) linearly.
Temperature of the gas
(a) Increases continuously
(b) Decreases continuously
(c) First increases to a maximum value then decreases
(d) First decreases to a minimum value then increases

Answer

A

Question. T1 and T2 represent the absolute temperatures of a given mass of an ideal gas undergoing isothermal changes AB and CD. Which of the following is correct? 

(a) T1 > T2
(b) T1 < T2
(c) T1 = T2
(d) T1 ≤ T2

Answer

A

Question. The heat absorbed by an ideal gas during one cycle of the cyclic process ABCD is 

(a) 10 J
(b) 20 J
(c) 40 J
(d) 30 J

Answer

B

Question. When ‘Q’ amount of heat energy is supplied to a diatomic gas, it does a work of ‘Q’/4. Then molar specific heat capacity of the process is
(a) 2/5R
(b) 5/2R
(c) 10/3R
(d) 6/7R

Answer

C

Question. With reference to the diagram (a) and (b) select the correct option (W refers to work done) 

1) Wa > Wb
(b) Wa < Wb
(c) Wa = Wb
(d) None of the above

Answer

B

Question. m kg ice is melted at 0ºC. Increase in entropy of the ice is (in SI units)
(a) Zero
(b) mLf /273
(c) mLf /373
(d) Infinity

Answer

B

Question. Slope of the adiabatic at A is 5/3 times the slope of the isothermal at A. The gas is  

(a) Monoatomic
(b) Diatomic
(c) Polyatomic
(d) Triatomic

Answer

A

Question. In the cyclic process shown by indicator diagram, the work done by the gas is 

(a) πP0V0
(b) 4πP0V0
(c) π/4 P0V0
(d) 3/4 π P0V0

Answer

A

Question. A thermodynamic system goes from state A to state C via a state B as indicated by P-V diagram. Find the work done by the gas for the process A → B → C

(a) –P0V0
(b) Zero
(c) –2P0V0
(d) –3P0V0

Answer

C

Question. P-V diagram for an ideal gas as is shown in figure. The work done by the gas during the process abcdef is 

(a) 8 P0V0
(b) 17 P0V0
(c) 5 P0V0
(d) 6 P0V0

Answer

D

Question. P-V graph for an ideal gas is shown in the figure. Corresponding P-T diagram will be   

Answer

C

Question. In an adiabatic process; the pressure and absolute temperature of a gas are related as P ∝ T3. Then, the value of Cp/Cv is
(a) 4/3
(b) 3/2
(c) 7/3
(d) 5/3

Answer

B

Question. The P–V diagram of a gas at constant temperature are drawn. The curve 1 is for a constant mass m1 and temperature T1 and curve T2 is for a constant mass m2 and temperature T2. Select the incorrect alternative 

(a) When T1 = T2, m2 > m1
(b) When m1 = m2, T2 > T1
(c) When T1 = T2, m1 > m2
(d) m1T1 < m2T2

Answer

C

Question. A polyatomic gas with six degree of freedom does 25J of work when it is expanded at constant pressure. The heat given to the gas is
(a) 100J
(b) 150J
(c) 200J
(d) 250J

Answer

A

Question. An ideal gas with adiabatic exponent 1.5 is heated at constant pressure. Fraction of heat absorbed used in increasing the temperature is
(a) 1/2
(b) 1/3
(c) 2/3
(d) 3/4

Answer

C

Question. A container have two part in which the gases are in the volume V1 and V2 under pressure P1 and P2 at same temperature. If the position of the separator is withdrawn the new pressure is    

Answer

A

Question. An ideal heat engine exhausting heat at 27°C have 40% efficiency. Then it takes heat from a reservoir at
(a) 127°C
(b) 227°C
(c) 327°
(d) 427°

Answer

B

Question. The pressure (P), volume V and temperature (T) of a certain gas are related as P = αT/V. Then the work done by the gas when temperature changes from T0 to 3T0 at constant pressure will be
(a) 2αT0
(b) 2α
(c) 2αT02
(d) 2α2T02

Answer

A

Question. One mole of an ideal monoatomic gas at temperature To expands slowly according to the law P/v = constant. If the final temperature is 2To, heat supplied to the gas is
(a) 2RTo
(b) 3/2 RTo
(c) RTo
(d) 1/2 RTo

Answer

A

Question. For a perfect gas the volume (V) versus temperature (T) graphs are drawn at pressures P1 and P2 as shown below. From the graphs, we can conclude that

(a) P1 < P2
(b) P1 > P2
(c) P1 = P2
(d) The information is insufficient to predict

Answer

B

Question. The following figure is the PV diagram for a cyclic process for an ideal gas. If the temperature in state B is 600 K, then the temperature in state C will be 

(a) 900 K
(b) 600 K
(c) 300 K
(d) 150 K

Answer

C

Question. Figure shows a cyclic process abca for one mole of an ideal gas. If a → b is isothermal process, then the which one represents P – T diagram for the given cyclic process  

Answer

C

Question. A refrigerator, whose coefficient of performance K = 5. extracts heat from the cooling compartment at the rate of 250 J/cycle. The work done per cycle to operate the refrigerator will be
(a) 30 J
(b) 50 J
(c) 40 J
(d) 20 J

Answer

B

Question. Which of the following can represent an adiabatic process (assuming each one of them represents either of the four processes –isothermal, –isochoric, –isobaric, –adiabatic) 

(a) 4
(b) 3
(c) 2
(d) 1

Answer

B

Question. Work done by the gas in the process AB is   

(a) P0V
(b) 2P0V
(c) Zero
(d) 4P0V

Answer

C

Question. If the thermodynamic process ABC is a semicircle, then work done in the process ABC is  

(a) + 2π unit
(b) –2π unit
(c) +4 unit
(d) –4 unit

Answer

A

Question. An ideal gas is supplied with Q amount of heat at constant volume to increase the temperature of gas by ΔT. If the same sample is supplied with heat at constant pressure, then to increase the temperature by the same amount heat must be (γ is the adiabatic exponent)
(a) Q′ = Q/γ
(b) Q′ = γQ
(c) Q′ = Q
(d) Q′ = (γ – 1)Q

Answer

B

Question. Find the work done by an ideal monoatomic gas during an adiabatic expansion shown in P-V diagram  

(a) (P1 – 2P2)V0
(b) 1/2 (P1 – 2P2)V0
(c) 3/2 (P1 – 2P2)V0
(d) 3/5 (P1 – 2P2)V0

Answer

C

Question. A Carnot engine takes heat from a reservoir at 627°C and rejects at 27°C. Calculate its efficiency
(a) 200 /209
(b) 3/5
(c) 1/3
(d) 2/3

Answer

D

Question. An ideal gas is taken round the cycle as shown on an PV diagram.   

Work done by the gas during the cycle is
(a) PoVo
(b) 2 PoVo
(c) – PoVo
(d) – PoVo/2

Answer

C

Question. The P–V diagram of 2g of Helium gas for a certain process A →B . is shown in figure. Heat given to the gas during the process is 

(a) PoVo
(b) 1.5 PoVo
(c) 4.5PoVo
(d) 6 PoVo

Answer

D

Question. According to the figure select the correct statement   

(a) The work in this process greater than isothermal process between A & B
(b) The corresponding V – T curve is a parabola
(c) Both (a) & (b) are correct
(d) Only (b) is correct

Answer

C

Question. One mole of an ideal monoatomic gas perform a cycle as shown in figure  

Mark correct option
(a) Work done in process AB is zero
(b) Work done in process BC is non-zero
(c) Work done in process CD is zero
(d) All of these

Answer

D

Question. A carnot engine working between 300K and 600K perform work of 800 Jper cycle. The amount of heat energy supplied to engine from the source in each cycle is
(a) 800J
(b) 1600J
(c) 3200J
(d) 6400J

Answer

B

Question. The P–V plot for two gases during adiabatic processes are shown in the figure. The graphs 1 and 2 should correspond respectively to 

(a) O2 and He
(b) He and O2
(c) O2 and CO
(d) N2 and O2

Answer

A