Light of uniform intensity shines perpendicularly on a totally absorbing surface, fully illuminating the surface.If the area of the surface is decreased:
A)the radiation pressure increases and the radiation force increases
B)the radiation pressure increases and the radiation force decreases
C)the radiation pressure stays the same and the radiation force increases
D)the radiation pressure stays the same and the radiation force decreases
E)the radiation pressure decreases and the radiation force decreases

Question

Quizplus · Accepted Answer

Radiation pressure is the pressure exerted by electromagnetic radiation on a surface. It is given by the formula P = I/c, where I is the intensity of the radiation and c is the speed of light. Since the intensity of the radiation is constant, if the area of the surface is decreased, the radiation pressure will stay the same.

However, radiation force is the force exerted by electromagnetic radiation on a surface, and it is given by the formula F = (P/c)A, where A is the area of the surface. Since the radiation pressure is constant and the area of the surface is decreased, the radiation force will decrease. Therefore, the best choice is D.

Light of Uniform Intensity Shines Perpendicularly on a Totally Absorbing