Question

Electromagnetic wave of intensity 1400 W/m² falls
on metal surface on area 1.5 m² is completely
absorbed by it. Find out force exerted by beam.
(1) 14 x 10-5 N (2) 14 x 10-6 N
(3) 7 x 10-5 N
(4) 7 x 10-6 N

Answer 1

$\huge\black{\underline{\bigstar{\mathtt{Answer!!}}}}$

(4) 7 * 10^-6 N

Explanation:

For a perfectly absorbing surface

F = IA/c

= (1400 W/m^2 * 1.5 m^2)/(3 * 10^8 m/s)

= 7 * 10^-6 N