A radiation of energy E falls normally on a perfectly reflecting surface. What is the momentum transferred to the surface ?

2\(\frac{E}{c}\)

Initial Momentum of photon $P_i = \frac{E}{c}$

Final Momentum of photon after reflection $P_f = \frac{E}{c}$

Change in momentum is $\Delta P = \frac{2P}{c}$

$\Rightarrow \text{Momentum Transfered }= \frac{2P}{c}$