Electromagnetic radiation of intensity I is made incident normally on a perfect nonreflecting surface (i.e perfect absorber). Then pressure developed on this surface would be …… .

Options

A. Ic
B. `Ic^(2)`
C. `(I)/(c )`
D. `(I)/(c^(2))`

Answer

C

Explanation

Pressure developed on a given surface,
`P_(S)=(F)/(A)=(((p)/(t)))/(A)=(p)/(At)=(((U)/(C )))/(At)=(U)/(ACt)=(I)/(C )`
(where p = momentum, U = radiant energy I = intensity of radiation `= (U)/(At)`)