Question

Two ideal gases $A$ and $B$ are kept in a closed container at room temperature. Consider collisions takes place between the molecules of $A$ and $B$.
Let $K_A^{{}^{\prime }}$ and $K_B^{{}^{\prime }}$ are the kinetic energies of molecule $A$ and $B$ respectively after collision and $K_A$ and $K_B$ are the kinetic energies of molecules $A$ and $B$ respectively before collision. Then choose the possible option(s)

• A. $K_A>K_A^{{}^{\prime }}$,$K_B>K_B^{{}^{\prime }}$
• B. $K_A<K_A^{{}^{\prime }}$,$K_B<K_B^{{}^{\prime }}$
• C. $K_A>K_A^{{}^{\prime }}$,$K_B<K_B^{{}^{\prime }}$
• D. $K_A<K_A^{{}^{\prime }}$,$K_B>K_B^{{}^{\prime }}$

Answer 1

Answer: (C), (D)

$K_A<K_A^{{}^{\prime }}$,$K_B>K_B^{{}^{\prime }}$

$C,D$
Collision takes place in ideal gases are elastic hence total kinetic energy will be conserved.
So, if energy of $A$ after the collision is increases then energy of $B$ decreases. Similarly, if energy of $A$ after the collision is decrease then energy of $B$ increases.