Two hydrogen atoms are in excited state with electrons residing in n = 2. First one is moving towards left and emits a photon of energy `E_(1)` towards right. Second one is moving towards left with same speed and emits a photon of energy `E_(2)` towards left. Taking recoil of nucleus into account during emission process

Options

A. `E_(1) gt E_(2)`
B. `E_(1) lt E_(2)`
C. `E_(1)=E_(2)`
D. information insufficient

Answer

B

Explanation

In the first case K.E. of H-atom increases due to recoil whereas in the second case K.E. decreases due to recoil
`:. E_(2) gt E_(1)`