For a plane electromagnetic wave,which of the following quantities has an average value of zero?

If the magnetic field in a plane electromagnetic wave is given by $\overrightarrow{B} = 3 \times 10^{-8} \sin (1.6 \times 10^{3} x + 48 \times 10^{10} t) \hat{j} \; T$,then what will be the expression for the electric field?

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:

What is the value of the speed of light in free space?

The electric field of a plane electromagnetic wave of wave number $k$ and angular frequency $\omega$ is given by $\vec{E} = E_0(\hat{i} + \hat{j}) \sin(kz - \omega t)$. Which of the following gives the direction of the associated magnetic field $\vec{B}$?

$A$ linearly polarized electromagnetic wave in vacuum is given by $E = 3.1 \cos \left[(1.8)z - (5.4 \times 10^6)t\right] \hat{i} \text{ N/C}$. It is incident normally on a perfectly reflecting wall at $z = a$. Choose the correct option.