Question

At what temperature is the rms velocity of hydrogen molecule equal to that of an oxygen molecule at 47°C ?

• A. 10 K
• B. 20 K
• C. 30 K
• D. 40 K

Answer 1

Answer: (B)

20 K

Answer 2

$V_{rms} = \sqrt{\frac{3RT}{M}}$

Now, rms velocity of $H_{2}$molecule = rms velocity of $O_{2}$molecules

$\sqrt{\frac{3R \times T}{2}} = \sqrt{\frac{3R \times (47 + 273)}{32}}$

$T = \frac{2 \times 320}{32} = 20K$