What is radiation pressure?

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

If the total energy transferred to a surface in time $t$ is $6.48 \times 10^5 \,J$, then the magnitude of the total momentum delivered to this surface for complete absorption will be:

$A$ beam of light with intensity $10^{-3} \text{ W m}^{-2}$ and cross-sectional area $20 \text{ cm}^2$ is incident on a fully reflective surface at an angle of $45^{\circ}$. The force exerted by the beam on the surface is:

$50\, W/m^2$ energy density of sunlight is normally incident on the surface of a solar panel. Some part of incident energy $(25\%)$ is reflected from the surface and the rest is absorbed. The force exerted on $1\, m^2$ surface area will be close to $(c = 3 \times 10^8\, m/s)$.

An impulse laser may be treated as a source of photons that are emitted during the time interval of the pulse,which is followed by a time interval when no photons are produced. Pulses are periodically repeated. $A$ laser beam of diameter $d = 10 \, \mu m$ is directed upward and is perpendicular to the thin foil surface which has a reflection coefficient $\rho = 0.50$ (see the sketch of the experiment). The reflection coefficient of the surface is the ratio of the reflected energy to the incident energy. $A$ pulse with duration of $0.13 \, ms$ has a total energy of $10 \, J$. What is the mass of the piece of foil that can be supported in the air solely by the light pressure of the laser beam? (Take $g = 10 \, m/s^2$)