JEE Main Thermodynamics Important Question for Session 1 Exam 2025

JEE Main Session 1 Physics Formula List 2025 for Exam Day

Cp and C, are specific heats at constant pressure and constant volume respectively. It
is observed that
Cp Ca for hydrogen gas
CpCb for nitrogen gas
The correct relation between a and b is

1. a=1/14b
2. a=b
3. a=14b
4. a=28b

An ideal gas undergoes a quasi-static, reversible process in which its molar heat capacity C remains constant. If during this process the relation of pressure P and volume V is given by PV" = constant, then n is given by (Here Cp and C, are molar specific heat at constant pressure and constant volume, respectively)

1. n= C-Cp/C-Cv
2. n = CP-C/C-Cu
3. n = C-C/C-Cp
4. n=Cp/Cv

For an adiabatic expansion of an ideal gas, the fractional change in its pressure is equal to (where g is the ratio of specific heats):

1. -V Y/dV
2. -V dV/V
3. 1 dV/ yV
4. dV/V

A diatomic gas, having Cp = R and Cy = R, is heated at constant pressure. The ratio dU: dQ: dW:

1. 5:7:2
2. 3:5:2
3. 3:7:2
4. 5:7:3

A half mole of an ideal monoatomic gas is heated at a constant pressure of 1 atm from 20°C to 90°C. Work done by the gas is close to (Gas constant R = 8.31J/molK)

1. 291J
2. 581J
3. 146J
4. 73J

A rigid diatomic ideal gas undergoes an adiabatic process at room temperature. The relation between temperature and volume for this process is TV = constant, then x is

1. 2/5
2. 2/3
3. 5/3
4. 3/5

In a process, the temperature and volume of one mole of an ideal monoatomic gas are varied according to the relation VT = K, where K is a constant. In this process, the temperature of the gas is increased by DT. The amount of heat absorbed by gas is (R is gas constant)

For the given cyclic process CAB as shown for a gas, the work done is

1. 30J
2. 10J
3. 5J
4. 1J

A gas can be taken from A and B via two different processes ACB and ADB. When path ACB is used 60 J of heat flows into the system and 30/ of work is done by the system. If path ADB is used work done by the system is 10 J. The heat flow into the system in path ADB is

1. 100J
2. 80J
3. 20J
4. 40J

One mole of diatomic ideal gas undergoes a cyclic process ABC. The process BC is adiabatic. The temperatures at A, B, and C are 400 K, 800 K, and 600 K respectively. Choose the correct statement.

1. The change in internal energy in the whole cyclic process is 250R
2. The change in internal energy in the process CA is 700R
3. The change in internal energy in the process AB is -350R
4. The change in internal energy in the process BC is-500R

The given diagram shows four processes i.e., isochoric, isobaric, isothermal, and adiabatic. The correct assignment of the processes, in the same order, is given by:

1. adcb
2. adbc
3. dabc
4. dacb