Question

An atom of mass M which is in the state of rest, emits a photon of wavelength $\lambda$ . As a result atom will deflect with the kinetic energy equation to (h is planck's constant).

• A. $\frac{h^2}{M{\lambda }^2}$
• B. $\frac{1}{2}\frac{h^2}{M{\lambda }^2}$
• C. $\frac{h}{M\lambda }$
• D. $\frac{1}{2}\frac{h}{M\lambda }$

Answer 1

The correct option is B $\frac{1}{2}\frac{h^2}{M{\lambda }^2}$

Momentum of photon, $p=\frac{h}{\lambda }$
Kinetic energy of photon of mass M, K$=\frac{P^2}{2M\lambda }$
or $K=\frac{h^2}{2M{\lambda }^2}$.