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

$A$ 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 . . . . . . .

$A$ lamp delivers a luminous flux of $100 \,W$ to an absorber of area $1 \,cm^2$. The force due to radiation pressure is

An astronaut floating freely in space decides to use his flashlight as a rocket. He shines a $10$ $W$ light beam in a fixed direction so that he acquires momentum in the opposite direction. If his mass is $80$ kg,how long must he shine the light to reach a velocity of $1$ $m/s$?

Light with an average flux of $20 \, W/cm^2$ falls on a non-reflecting surface at normal incidence having a surface area of $20 \, cm^2$. The energy received by the surface during a time span of $1 \, minute$ is $............ \, J$.

Find the compression in the spring with spring constant $K = 5 \ N/m$ which is attached to a metal plate of area $50 \ m^2$. Light of intensity $I = 40 \ MW/m^2$ is incident at an angle of $60^o$ on the metal plate,and the coefficient of reflection is $\rho = 0.5$ for the plate. (in $m$)