Sun light falls normally on a surface of area 36 cm ^ 2 and exerts...

The radiation pressure in case of complete absorption is given by,

$P = \dfrac{I}{c}$.

Therefore, the force will be,

$F = \dfrac{I}{c} \times A ⇒ I = \dfrac{Fc}{A}$

$⇒ I = \dfrac{7 . 2 \times {10}^{- 9} \times 3 \times {10}^{8}}{36 \times {10}^{- 4}} = 600W{m}^{- 2} ⇒ I = 0 . 06W{cm}^{- 2}$