The magnetic field in a plane electromagnetic wave is given as $$\mathbf{B}=\left(3 \times 10^{-7} \mathrm{~T}\right) \sin \left(3 \times 10^4 x+9 \times 10^{12} t\right) \hat{j}$$

The electric field of this wave is given as

Frequencies in the UHF range normally propagate by means of

A light of intensity $$12 \mathrm{Wm}^{-2}$$ incidents on a black surface of area $$4 \mathrm{~cm}^2$$. The radiation pressure on the surface is