Question

A sealed container with negiligible coefficient of volumetric expansion contains helium (a monatomic gas). When it is heated from 300 K to 600 K, the average KE of helium atoms is
A. halved
B. unchanged
C. doubled
D. increased by factor `sqrt2`

Answer 1

Correct Answer - C
As, kinetic enregy of gas is given as
`" "K=1/2mv_(rms)^(2)`
Also,`" "v_(rms)=sqrt((3KT)/M)`
Now, `v_(rms)prop sqrtT rArr(K_(2))/(K_(1))=[((v_(rms))_(2))/((v_(rms))_(1))]=[sqrt(T2)/sqrt(T_(1))]^(2)`
`rArr" "K_(2)=K_(1)((T_(2))/(T_(1)))rArrK_(2)=K_(1)((600)/(300))`
`therefore" "K_(2)=2K_(1)`