JEE Advanced levelSingle correct optionDifficulty 3 of 3ig200
At 300K a gas sample has a Maxwell distribution with most probable speed u0. The temperature at which the fraction of molecules having speed u0 becomes maximum in the distribution of a gas with double the molar mass is
A600K
B150K
C300K
D1200K
Answer: A
The fraction at speed u0 is a maximum when u0 is the most probable speed of the heavier gas: 2RT′/(2M)=2R(300)/M, so T′/2=300, T′=600K.