The efficiency of a bulb of power $60 \ W$ is $16 \%$. The peak value of the electric field produced by the electromagnetic radiation from the bulb at a distance of $2 \ m$ from the bulb is $\left(\frac{1}{4 \pi \epsilon_0}=9 \times 10^9 \ Nm^2 C^{-2}\right)$ (in $Vm^{-1}$)

An electromagnetic wave of frequency $1 \times 10^{14} \,Hz$ is propagating along the $z$-axis. The amplitude of the electric field is $4 \,Vm^{-1}$. What is the energy density of the electric field? (Permittivity of free space $\varepsilon_0 = 8.8 \times 10^{-12} \,C^2 \,N^{-1} \,m^{-2}$)

$A$ plane electromagnetic wave propagating in the direction of the unit vector $\hat{n}$ with a speed $c$ is described by electric and magnetic field vectors $E$ and $B$,respectively. Which of the following relations (in $SI$ units) between $E$ and $B$ can be ruled out on dimensional grounds alone?

The magnetic field in a plane electromagnetic wave is given by $B = 3.01 \times 10^{-7} \sin(6.28 \times 10^2 x + 2.2 \times 10^{10} t) \, T$,where $x$ is in $cm$ and $t$ is in seconds. The wavelength of the given wave is ....... $cm$.

$A$ plane electromagnetic wave of frequency $25 \text{ MHz}$ travels in free space along the $X$-direction. At a particular point in space and time,the magnetic field is $\overrightarrow{B} = 2.1 \times 10^{-8} \hat{k} \text{ T}$. Find the electric field $\overrightarrow{E}$ at this point.

In the propagation of electromagnetic waves,the angle between the direction of propagation and the plane of polarisation is (in $^{\circ}$)