For an electromagnetic wave propagating through vacuum,$\vec{k}$,$\vec{E}$,and $\omega$ represent the propagation vector,electric field,and angular frequency,respectively. The magnetic field associated with this wave is represented by:

In a plane electromagnetic wave,the electric field oscillates sinusoidally at a frequency of $2.0 \times 10^{10} \; Hz$ and amplitude $48 \; V m^{-1}$.
$(a)$ What is the wavelength of the wave?
$(b)$ What is the amplitude of the oscillating magnetic field?
$(c)$ Show that the average energy density of the $E$ field equals the average energy density of the $B$ field. $[c = 3 \times 10^{8} \; m s^{-1}]$.

Pick out the statement which is not true.

Select the incorrect statement regarding electromagnetic waves.

$A$ plane electromagnetic wave of wavelength $3.0 \ m$ travels in vacuum along the positive $X$-axis. The electric field of amplitude $300 \ Vm^{-1}$ oscillates parallel to the $Y$-axis. Then the intensity of the wave is $(\mu_0 = 4\pi \times 10^{-7} \ Hm^{-1}, c = 3 \times 10^8 \ ms^{-1})$ (in $Wm^{-2}$)

$A$ point light source emits electromagnetic ($E$.$M$.) waves in free space. $A$ detector,placed at a distance of $L \text{ m}$,measures the intensity as $I_o$. The detector is now shifted to another location on the same spherical surface,ensuring the angle between the original location and the new location is $45^{\circ}$. The measured intensity at the new location will be . . . . . . .