If $c$ is the speed of electromagnetic waves in vacuum,its speed in a medium of dielectric constant $K$ and relative permeability $\mu_r$ is:

$X$-rays,gamma rays and microwaves travelling in vacuum have

Given below are two statements:
Statement $I$: Electromagnetic waves carry energy as they travel through space and this energy is equally shared by the electric and magnetic fields.
Statement $II$: When electromagnetic waves strike a surface,a pressure is exerted on the surface.
In the light of the above statements,choose the most appropriate answer from the options given below:

The electric field of an electromagnetic wave in free space is represented as $\vec{E} = E_0 \cos(\omega t - kz) \hat{i}$. The corresponding magnetic induction vector will be:

The average power output of a point source of an electromagnetic radiation is $1080 \,W$. The maximum value of the rms value of the electric field at a distance of $3 \,m$ from the source is (in $\,Vm^{-1}$)

The electric field in an electromagnetic wave is given by $E = (50 \, NC^{-1}) \sin \omega(t - x/c)$. The energy contained in a cylinder of volume $V$ is $5.5 \times 10^{-12} \, J$. The value of $V$ is $...... \, cm^3$ (given $\epsilon_0 = 8.8 \times 10^{-12} \, C^2 N^{-1} m^{-2}$).