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Kinetic Theory · Question 1

JEE Main 2026 (Online) 6th April Morning ShiftMCQMedium📈 Topic in 23% papers+4−1
1

Two closed vessels of same volume are joined through a narrow tube and both vessels are filled with air of pressure 90 kPa and temperature 400 K. Keeping the temperature of one vessel constant at 400 K the second vessel temperature is raised to 500 K. The final pressure in the vessels is kPa.

  1. 100
  2. 120
  3. 90
  4. 105

Answer

(1) 100

Solution

Total moles are conserved; finally both vessels have the same pressure P:

n1+n2=n1'+n2'

P0VR(400)+ P0VR(400)= PVR(400)+ PVR(500)

⇒ 2 90400=P ( 1400+ 1500 )

⇒ 0.45=P 92000

∴ P= 0.45 20009=100 kPa

Answer: (1)

JEE Main 2026 (Online) 6th April Morning Shift

Keep practising — Kinetic Theory

2

If 2 mole of an ideal monoatomic gas at temperature T, is mixed with 6 mole of another ideal monoatomic gas at temperature 2T then the temperature of mixture is :

  1. 52T
  2. 54T
  3. 72T
  4. 74T
JEE Main 2026 (Online) 6th April Evening Shift
3

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Choose the correct answer from the options given below :

  1. Both (A) and (R) are true and (R) is the correct explanation of (A)
  2. Both (A) and (R) are true but (R) is NOT the correct explanation of (A)
  3. (A) is true but (R) is false
  4. (A) is false but (R) is true
JEE Main 2026 (Online) 5th April Morning Shift
4

An ideal gas at pressure P and temperature T is expanding such that PT3 = constant. The coefficient of volume expansion of the gas is .

  1. 2T
  2. 1T
  3. 4T
  4. 3T
JEE Main 2026 (Online) 5th April Evening Shift
5

One gas of n1 mole of molecules at temperature T1, volume V1, and pressure P1, and another gas of n2 mole of molecules at temperature T2, volume V2, and pressure P2, are mixed resulting in pressure P and volume V of the mixture. The temperature of the mixture is .

  1. (T1+T2)2
  2. T1T2PVT2P1V1+T1P2V2
  3. (T2P1V1+T1P2V2)T1T2PV
  4. |T1-T2|2
JEE Main 2026 (Online) 4th April Morning Shift
6

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Choose the correct answer from the options given below :

  1. Both (A) and (R) are true and (R) is the correct explanation of (A)
  2. Both (A) and (R) are true but (R) is NOT the correct explanation of (A)
  3. (A) is true but (R) is false
  4. (A) is false but (R) is true
JEE Main 2026 (Online) 4th April Evening Shift
7

A mixture of carbon dioxide and oxygen has volume 8310 cm3, temperature 300 K, pressure 100 kPa and mass 13.2 g. The number of moles of carbon dioxide and oxygen gases in the mixture respectively are . (Assume both carbon dioxide and oxygen gases behave like ideal gases) [R = 8.31 J/mol K]

  1. 0.15 and 0.18
  2. 0.25 and 0.08
  3. 0.21 and 0.12
  4. 0.13 and 0.20
JEE Main 2026 (Online) 2nd April Evening Shift
8

The mean free path of a molecule of diameter 5 10-10 m at the temperature 41 C and pressure 1.38 105 Pa, is given as m. (Given kB = 1.38 10-23 J/K).

  1. 2 2 10-10
  2. 10 2 10-8
  3. 2 2 10-8
  4. 2 10-8
JEE Main 2026 (Online) 28th January Evening Shift
9

Consider two boxes containing ideal gases A and B such that their temperatures, pressures and number densities are same. The molecular size of A is half of that of B and mass of molecule A is four times that of B. If the collision frequency in gas B is 32 1018 /s then collision frequency in gas A is /s.

  1. 8 1018
  2. 2 1018
  3. 32 1018
  4. 4 1018
JEE Main 2026 (Online) 22nd January Evening Shift
10

An insulated cylinder of volume 60 cm3 is filled with a gas at 27 and 2 atmospheric pressure. Then the gas is compressed making the final volume as 20 cm3 while allowing the temperature to rise to 77 . The final pressure is atmospheric pressure.

JEE Main 2026 (Online) 22nd January Evening Shift
11

The r.m.s. speed of oxygen molecules at 47 is equal to that of the hydrogen molecules kept at . (Mass of oxygen molecule/mass of hydrogen molecule = 32/2)

  1. -100
  2. -253
  3. -20
  4. -235
JEE Main 2026 (Online) 21st January Evening Shift

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