JEE Main & Advanced JEE Main Paper (Held on 09-4-2019 Morning)

  • question_answer For a given gas at 1 atm pressure, rms speed of the molecule is 200 m/s at \[127{}^\circ C.\] At 2 atm pressure and at\[~227{}^\circ C,\]the rms speed of the molecules will be :             [JEE Main 9-4-2019 Morning]

    A) \[80\text{ }m/s\]                      

    B) 100 5 m/s

    C) \[80\sqrt{5}m/s\]                    

    D) \[100\text{ }m/s\]

    Correct Answer: B

    Solution :

    \[{{V}_{rms}}=\sqrt{\frac{3RT}{{{M}_{\text{w}}}}}\Rightarrow {{\text{v}}_{rms}}\propto \sqrt{T}\] Now,\[\frac{\text{v}}{200}=\sqrt{\frac{500}{400}}\Rightarrow \frac{\text{v}}{200}=\frac{\sqrt{5}}{2}\] \[\Rightarrow \text{v}=100\sqrt{5}m/s\] Option

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