What is the force exerted on a surface having an area of $10\, cm^2$ due to the radiation of the Sun?

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

Radiation of intensity $I$ is falling obliquely on a surface. The area of the surface exposed to radiation is $A$. The angle of incidence with the normal is $\theta$. Select the correct alternative,where $\beta$ is a constant that depends upon the nature of the surface.

$A$ laser beam with wavelength $\lambda = 633 \ nm$ has a power of $3 \ mW$. If the cross-sectional area of the beam is $3 \ mm^2$,what is the pressure exerted by the beam on a surface? (Assume the surface is a perfect reflector and the light is incident normally.)

Light is incident normally on a completely absorbing surface with an energy flux of $25\,W\,cm^{-2}.$ If the surface has an area of $25\,cm^2,$ the maximum momentum transferred to the surface in $40\,min$ time duration will be

$A$ $1.5 \,kW$ 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 ......... $kg$.