In an apparatus, the electric field was found to oscillate with an amplitude of $18 \text{ V/m}$. The magnitude of the oscillating magnetic field will be:

The sun delivers $10^{3} \,W m^{-2}$ of electromagnetic flux on the Earth's surface. The total power that is incident on a roof of dimensions $6 \,m \times 30 \,m$ is . . . . . . .

If the relative permeability and dielectric constant of a medium are $\mu_r$ and $K$ respectively,then the refractive index $n$ of the medium is:

In a plane electromagnetic wave,the maximum value of the electric field component is $4.4 \ Vm^{-1}$. The intensity of the wave is nearly (in $mW \ m^{-2}$)

The electric field of an electromagnetic wave in free space is given by $\vec E = 10 \cos (10^7 t + kx) \hat j \, V/m$,where $t$ and $x$ are in seconds and metres respectively. It can be inferred that:
$(1)$ The wavelength $\lambda$ is $188.4 \, m$.
$(2)$ The wave number $k$ is $0.33 \, rad/m$.
$(3)$ The wave amplitude is $10 \, V/m$.
$(4)$ The wave is propagating along $+x$ direction.
Which one of the following pairs of statements is correct?

For electromagnetic waves,the phase difference between the $\vec{E}$ and $\vec{B}$ vectors (for the region far from the source) is......