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Kinetic Theory

JEE Main level, single correct, medium

17 of 168

Question 17 of 168

The temperature of an open room of volume $30{m}^{3}$ increases from $17^{\circ}C$ to $27^{\circ}C$ due to the sunshine. The atmospheric pressure in the room remains $1\times {10}^{5}Pa$ . If ${n}_{i}$ and ${n}_{f}$ are the number of molecules in the room before and after heating, then ${n}_{f}-{n}_{i}$ will be:

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Answer: (A) $-2.5\times {10}^{25}$

{T}_{i}=273+17=290K

{T}_{f}=273+27=300K

From ideal gas equation,

PV=nRT\Rightarrow n=\dfrac{PV}{RT}

{n}_{f}-{n}_{i}=\dfrac{PV}{R}\left[\dfrac{1}{{T}_{f}}-\dfrac{1}{{T}_{i}}\right]

=-2.5\times {10}^{25}

JEE Main question paper PDF

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JEE Main 2025 Apr 2 Shift 1 question paper

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