question_answer

A radiation of energy E falls normally on d perfectly reflecting surface. The momentum transferred to the surface is            [AIEEE 2004]

A) \[E/c\]

B) \[2E/c\]

C) \[Ec\]

D) \[E/{{c}^{2}}\]

Correct Answer: B

Solution :

[b] Initial momentum of surface

where c = velocity of light (constant).

Since, the surface is perfectly reflecting, so the same momentum will be reflected completely.

Final momentum,

(with negative value)

Change in momentum

Thus, momentum transferred to the surface is