# The pressure exerted by an electromagnetic wave of Intensity I on a non-reflecting surface is

Q: The pressure exerted by an electromagnetic wave of Intensity I(W/m2) on a non-reflecting surface is (c = velocity of light)

(a) I c

(b) I c2

(c) I/c

(d) I/c2

Sol: $\large Intensity = \frac{Energy}{Area \times time}$

$\large I = \frac{F \times s}{A \times t} = \frac{F \times c}{A}$

$\large \frac{I}{c} = \frac{F}{A}$

$\large \frac{I}{c} = P$ ( Pressure = Force/Area )

Ans: (c)