An electromagnetic wave has its electric and magnetic fields given by

$$ \mathbf{E}(t)=\mathbf{E}_m \sin (k x-\omega t) ; \quad \mathbf{B}(t)=\mathbf{B}_m \sin (k x-\omega t) $$

If the direction of $\mathbf{E}_m$ and $\mathbf{B}_m$ are in the direction of $(\hat{\mathbf{i}}+\hat{\mathbf{j}})$ and $(\hat{\mathbf{i}}-\hat{\mathbf{j}})$ respectively, the unit vector that gives the direction of propagation of the wave is

A beam of white light is incident normally on a plane surface absorbing 70\% of the light and reflecting the rest. If the incident beam carries 10 W of power, the force exerted by it on the surface is

An electromagnetic wave is propagating in vacuum along $-\hat{\mathbf{j}}$ direction. The magnetic field of the wave is given by $\mathbf{B}=\left(2 \times 10^{-8}\right) \cos \left[\pi \times 10^{15}\left(t+\frac{y}{c}\right)\right] \hat{\mathbf{k}} \mathrm{T}$. The electric field $\mathbf{E}$ of this wave is ( $c \equiv$ speed of light)

The radiation energy emitted per second by a point source is 100 W . If the efficiency of the source is $4 \%$, then the rms value of the electric field at distance of 2 m is [use $\frac{1}{4 \pi \varepsilon_0}=9 \times 10^9$ in SI unit]