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Thermodynamics (Physics) · Question 28

JEE Main 2025 (Online) 2nd April Morning ShiftMCQEasy📈 Topic in 52% papers+4−1
1

In an adiabatic process, which of the following statements is true?

  1. The internal energy of the gas decreases as the temperature increases
  2. The molar heat capacity is zero
  3. Work done by the gas equals the increase in internal energy
  4. The molar heat capacity is infinite

Answer

(2) The molar heat capacity is zero

Solution

Adiabatic process: Q = 0, while ΔT ≠ 0

C = Qn T = 0

(1) is wrong: internal energy of an ideal gas increases with temperature.

(3) is wrong: U = -W, i.e. work done by the gas equals the decrease in internal energy.

(4) is wrong: C is infinite for an isothermal process (ΔT = 0).

Answer: (2)

JEE Main 2025 (Online) 2nd April Morning Shift

Keep practising — Thermodynamics (Physics)

2

Identify the characteristics of an adiabatic process in a monoatomic gas. Choose the correct answer from the options given below :

  1. (B), (D) only
  2. (B), (E) only
  3. (A), (C), (E) only
  4. (A), (C), (D) only
JEE Main 2025 (Online) 2nd April Evening Shift
3

The work done in an adiabatic change in an ideal gas depends upon only :

  1. change in its pressure
  2. change in its temperature
  3. change in its specific heat
  4. change in its volume
JEE Main 2025 (Online) 29th January Morning Shift
4

A Carnot engine (E) is working between two temperatures 473 K and 273 K. In a new system two engines - engine E1 works between 473 K to 373 K and engine E2 works between 373 K to 273 K. If 12, 1 and 2 are the efficiencies of the engines E, E1 and E2, respectively, then

  1. 12 = 1 2
  2. 12 = 1 + 2
  3. 12 1 + 2
  4. 12 < 1 + 2
JEE Main 2025 (Online) 28th January Morning Shift

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