What is the force exerted by a photon of intensity `1.4 k W m^(-2)` if it falls on a perfect absorber of radius 2 m ?

Options

A. `2.35 xx 10^(-4)` N
B. `10^(8) N`
C. `8.35 xx 10^(4)` N
D. `8.8 xx 10^(-8) N`

Answer

A

Explanation

`F_(ex) = (P)/(c ) = (IA)/( c)`
`I = 1.4 xx 10^(3) W m^(-2)`
`A = 4 pi r^(2) = 4xx 3.14 xx (2)^(2) m^(2)`
`F_(ex) = 2.35 xx 10^(-4)` N