Question

Electromagnetic waves are incident normally on a perfectly reflecting surface having surface area \( A \). If \( I \) is the intensity of the incident electromagnetic radiation and \( c \) is the speed of light in vacuum, the force exerted by the electromagnetic wave on the reflecting surface is

• A. \( \frac{2IA}{c} \)
• B. \( \frac{IA}{c} \)
• C. \( \frac{IA}{2c} \)
• D. \( \frac{I}{2Ac} \)

Answer 1

The Correct Option is A

The force exerted on the reflecting surface by the incident electromagnetic wave is given by:
\( F = \frac{2IA}{c} \) where \( I \) is the intensity of the incident wave, \( A \) is the area of the reflecting surface, and \( c \) is the speed of light in vacuum.
This equation arises from the momentum transfer of the electromagnetic wave to the reflecting surface.