Kinetic Theory of Gases · JEE Main previous year questions

2026 3 questions

1. Q482026 · 6 Apr 2026 · Shift 1· Numerical answer

   The energy released when $\frac{7}{17.13}\mathrm{kg}$ of ${}_3^7\mathrm{Li}$ is converted into ${}_2^4\mathrm{He}$ by proton bombardment is $\alpha \times 10^{32}\mathrm{eV}$. The value of $\alpha$ is ____. (Nearest integer) (Mass of ${}_3^7\mathrm{Li}=7.0183\mathrm{u}$, mass of ${}_2^4\mathrm{He}=4.004\mathrm{u}$, mass of proton $=1.008\mathrm{u}$ and $1\mathrm{u}=931MeV/{\mathrm{c}}^2$ and Avogadro number $=6.0\times 10^{23}$)

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   Answer: 6

2. Q272026 · 28 Jan 2026 · Shift 2

   The mean free path of a molecule of diameter $5\times 10^{-10}\text{ m}$ at the temperature $41^{\circ }\text{C}$ and pressure $1.38\times 10^5\text{ Pa}$, is given as ________ m. (Given $k_B=1.38\times 10^{-23}\text{ J/K}$).

   1. A.$2\sqrt{2}\times 10^{-10}$
   2. B.$10\sqrt{2}\times 10^{-8}$
   3. C.$2\sqrt{2}\times 10^{-8}$
   4. D.$2\times 10^{-8}$
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   Answer: C

3. Q402026 · 22 Jan 2026 · Shift 1

   The volume of an ideal gas increases 8 times and temperature becomes $(1/4{)}^{\text{th}}$ of initial temperature during a reversible change. If there is no exchange of heat in this process $(\Delta \mathrm{Q}=0)$ then identify the gas from the following options (Assuming the gases given in the options are ideal gases) :

   1. A.$\mathrm{N}{\mathrm{H}}_3$
   2. B.${\mathrm{O}}_2$
   3. C.$\mathrm{C}{\mathrm{O}}_2$
   4. D.He
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   Answer: D