A small mirror of mass m is suspended by a massless thread of length $$l$$. Then the small angle through which the thread will be deflected when a short pulse of laser of energy E falls normal on the mirror (c = speed of light in vacuum and g = acceleration due to gravity)

A

$$\theta = \dfrac{3E}{4mc\sqrt{gl}}$$

B

$$\theta = \dfrac{E}{mc\sqrt{gl}}$$

C

$$\theta = \dfrac{E}{2mc\sqrt{gl}}$$

D

$$\theta = \dfrac{2E}{mc\sqrt{gl}}$$