[SOLVED] An EM wave of intensity I falls on a surface kept in vacuum and exerts radiation pressure p on it.

An EM wave of intensity I falls on a surface kept in vacuum and exerts radiation pressure p on it. Which of the following are true ?

(a) Radiation pressure is I/c if the wave is totally absorbed
(b) Radiation pressure is -I/c if the wave is totally reflected
(c) Radiation pressure is 2I/c if the wave is totally reflected
(d) Radiation pressure is in the range I/c < p < 2I/c for real surfaces

Answer:

The correct answer for  An EM wave of intensity I falls on a surface kept in vacuum and exerts radiation pressure p on it. Which of the following are true ?

(a, c, d)

Key concept: Radiation pressure (p) is the force exerted by electromagnetic wave on unit area of the surface, i.e., rate of change of momentum per unit area of the surface.

Let us consider a surface exposed to electromagnetic radiation as shown in figure. The radiation is falling normally on the surface. Further, intensity of radiation is I and area of surface exposed to radiation is 

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