$A$ laser beam has intensity $2.1 \times 10^{15} \ W/m^2$. The amplitude of the magnetic field in the beam is approximately: (in $T$)

When an $EM$ wave propagates through a vacuum,then:

If the magnetic field in a plane progressive wave is represented by the equation $B_{y} = 2 \times 10^{-7} \sin(0.5 \times 10^3 x + 1.5 \pi \times 10^{11} t) \ T$,then the frequency of the wave is (In the equation,time $t$ is in seconds).

Consider an electromagnetic wave propagating in a vacuum. Choose the correct statement.

The speed of an electromagnetic wave in a vacuum depends upon the source of radiation.

For a plane electromagnetic wave,the electric field is given by $\vec{E} = 10 \cos(10^7t + kx) \hat{j} \text{ V/m}$. Where $t$ is in seconds and $x$ is in meters,then: $(i)$ The wavelength of this wave is $188.4 \text{ m}$. $(ii)$ The wave vector of this wave is $0.33 \text{ rad/m}$. $(iii)$ The amplitude of the electric field of this wave is $10 \text{ V/m}$. $(iv)$ This wave is propagating in the positive $X$-direction.