Question

The radiation force experienced by body exposed to radiation of intensity I, assuming surface of body to be perfectly absorbing is:

• A. $\frac{\pi R^{2}I}{c}$
• B. $\frac{\pi RHI}{c}$
• C. $\frac{IRH}{2c}$
• D. $\frac{IRH}{c}$

Answer 1

The correct option is D $\frac{IRH}{c}$

Effective area = $\frac{1}{2}.2R.H=RH$

Radiation pressure = $\frac{I}{c}$

$\therefore Force=pressure\times area$

$=\frac{I}{c}\times RH$

$=\frac{IRH}{c}$