Question 688: Thermodynamics & KTG

Question

The r.m.s. speed of gas molecules at 800 K will be

Accepted Answer

We need to use the formula for the
root mean square (r.m.s.) speed
:
$ v_{	ext{rms}} = \sqrt{\frac{3kT}{m}} $
So,
$ v_{	ext{rms}} \propto \sqrt{T} $
We are asked to compare $v_{	ext{rms}}$ at $T = 800 \,K$ with that at $T = 200 \,K$.
$ \frac{v_{800}}{v_{200}} = \sqrt{\frac{800}{200}} = \sqrt{4} = 2 $
Thus, the r.m.s. speed at 800 K is
twice
the value at 200 K.
Ã¢ÂÂ Correct Answer:
Option B: twice the value at 200 K

Answer

same as at 200 K

Answer

twice the value at 200 K

Answer

four times the value at 200 K

Answer

half the value at 200 K

Thermodynamics & KTG

The r.m.s. speed of gas molecules at 800 K will be

Choose the correct answer: