Question

Three different sources are emitting $\gamma -$rays, $X-$rays and ultraviolet rays respectively. If the intensity of all the sources is the same and the rays are incident normally on areas and of the same magnitude, which radiation will exert more pressure on the area ? Assume $100\%$ absorption of radiation by each area.

• A. $\gamma -$rays
• B. $X-$rays
• C. Ultraviolet rays
• D. All three will exert the same pressure

Answer 1

The correct option is D All three will exert the same pressure

The radiation pressure is given by,
$P=\frac{F}{A}=\frac{I}{c}$

As $I\text{and}c$ both are same for all radiations, so all of them will exert the same pressure.

Hence, $\left(D\right)$ is the correct answer.