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For a given gas at 1 atm pressure, rms speed of the molecules is 200 m/s at 127°C. At 2 atm pressure and at 227°C, the rms speed of the molecules will be

Asked in JEE Main 9th April 1st Shift 2019 · Speed with temperature and molar mass

Answer: (2) 100√5 m/s

Step-by-step solution

vᵣₘₛ=√(3RT)/M: the pressure does not appear, so the change from 1 atm to 2 atm is a distraction.

T₁=127+273=400 K and T₂=227+273=500 K.

v₂=v₁√(T₂)/(T₁)=200√(500)/(400).

=200×(√5)/2=100√5≈223.6 m/s.

Why the other options are wrong

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