The magnitude of the electric field of a plane electromagnetic wave travelling in free space is $E$. If $\mu_0$ and $\varepsilon_0$ are respectively permeability and permittivity of the free space,then the magnitude of magnetic field of the wave is

The electric field in a plane electromagnetic wave is given by $\overrightarrow{E} = 200 \cos \left[ (0.5 \times 10^{3} \text{ m}^{-1}) x - (1.5 \times 10^{11} \text{ rad/s}) t \right] \hat{j} \text{ V/m}$. If this wave falls normally on a perfectly reflecting surface having an area of $100 \text{ cm}^{2}$,and the radiation pressure exerted by the electromagnetic wave on the surface is $\frac{x}{10^{9}} \text{ N/m}^{2}$,find the value of $x$.

Given below are two statements: one is labelled as Assertion $(A)$ and other is labelled as Reason $(R).$
Assertion $(A):$ Electromagnetic waves carry energy but not momentum.
Reason $(R):$ Mass of a photon is zero.
In the light of the above statements,choose the most appropriate answer from the options given below:

The velocity factor of a transmission line is $x$. If the dielectric constant of the medium is $2.6$,the value of $x$ is:

Choose the correct statement.

The ratio of the average electric energy density to the total average energy density of an electromagnetic wave is: