Kinetic Theory Ques 14
14. $N$ molecules each of mass $m$ of a gas $A$ and $2$ $ N$ molecules each of mass $2 $ $m$ of gas $B$ are contained in the same vessel which is maintained at temperature $T$. The mean square velocity of molecules of $B$ type is $v^{2}$ and the mean square rectangular component of the velocity of $A$ type is denoted by $\omega^{2}$. Then $\omega^{2} / v^{2}$
[1991]
(a) 2
(b) 1
(c) $1 / 3$
(d) $2 / 3$
Show Answer
Answer:
Correct Answer: 14.(d)
Solution:
- (d) The mean square velocity of A type molecules $=\omega^{2}+\omega^{2}+\omega^{2}=3 \omega^{2}$
Therefore, $\frac{1}{2} m(3 \omega^{2})=\frac{1}{2}(2 m) v^{2}$
This gives $\omega^{2} / v^{2}=2 / 3$
Mean kinetic energy of the two types of molecules should be equal.