Average force exerted on a non-reflecting surface at normal incidence is $2.4 \times 10^{-4} \,N$. If $360 \,W/cm^2$ is the light energy flux during a span of $1$ hour $30$ minutes,then the area of the surface is: (in $\,m^2$)

If $P$ represents radiation pressure,$c$ represents the speed of light,and $Q$ represents radiation energy striking a unit area per second,then non-zero integers $x, y,$ and $z$ such that $P^x Q^y c^z$ is dimensionless are:

$A$ bulb of power $660 \,W$ radiates uniformly in all directions. The pressure exerted by the radiation on the surface at a distance of $5 \,m$ is

$A$ pulse of light of duration $100 \ ns$ is absorbed completely by a small object initially at rest. The power of the pulse is $30 \ mW$ and the speed of light is $3 \times 10^8 \ m/s$. The final momentum of the object is:

$A$ radiation of energy $E$ falls normally on a perfectly reflecting surface. The momentum transferred to the surface is ($C =$ velocity of light).

$A$ $1.5 \,kW$ laser beam of wavelength $6400 \,\mathring A$ is used to levitate a thin aluminium disc of the same area as the cross-section of the beam. The laser light is reflected by the aluminium disc without any absorption. The mass of the foil is close to ......... $kg$.