The radiation pressure $1 \,m$ away from a $330 \,W$ electric bulb is

$A$ light with an energy flux of $18 \,W \,cm^{-2}$ falls on a non-reflecting surface at normal incidence. If the surface has an area of $20 \,cm^2$, the average force exerted on the surface during a $30$ minute time span is . . . . . . $\left(c=3 \times 10^8 \,ms^{-1}\right)$.

$A$ bulb of $800 \text{ W}$ electrical power has an efficiency of $3 \%$. It is kept at the centre of a sphere of diameter $20 \text{ cm}$. The force exerted on its surface by the electromagnetic $(EM)$ wave is . . . . . . .

Radiations of intensity $0.5 \ Wm^{-2}$ are striking a metal plate. The pressure exerted on the plate is:

$A$ parallel beam of light is incident normally on a plane surface absorbing $50\%$ of the light and reflecting the rest. If the incident beam carries $90 \text{ W}$ of power,the force exerted by it on the surface is ($C = 3 \times 10^8 \text{ m/s}$ is the velocity of light in air).

The radiation pressure exerted by a $450 \ W$ light source on a perfectly reflecting surface placed at $2 \ m$ away from it is: