Question

A radiation is incident normally on a surface of area $A$ which reflects fraction $r$ of the incident radiation. If the force exerted by the radiation on the surface is $F$, then its intensity is

• A. $$\frac{FC}{rA}$$
• B. $$\frac{FC}{(1+r)A}$$
• C. $$\frac{(1+r)FC}{A}$$
• D. $$\frac{rFC}{A}$$

Answer 1

The correct option is B $$\frac{FC}{(1+r)A}$$

$$F=\frac{I[1+r]}{C}A\Rightarrow I=\frac{FC}{(1+r)A}$$