Consider the following:
$I.$ Waves created on the surfaces of a water pond by a vibrating source.
$II.$ Wave created by an oscillating electric field in air.
$III.$ Sound waves travelling under water.
Which of these can be polarized?

Assertion $(A)$: Electromagnetic waves exert pressure,called radiation pressure.
Reason $(R)$: This is because they carry energy.

The rms value of the electric field of an electromagnetic wave emitted by a source is $660 \ NC^{-1}$. The average energy density of the electromagnetic wave is

The speed of electromagnetic waves is the same for all ........

An electromagnetic wave has its electric and magnetic fields given by $\vec{E}(t) = \vec{E}_m \sin(kx - \omega t)$ and $\vec{B}(t) = \vec{B}_m \sin(kx - \omega t)$. If the directions of $\vec{E}_m$ and $\vec{B}_m$ are in the direction of $\hat{i} + \hat{j}$ and $\hat{i} - \hat{j}$ respectively,the unit vector that gives the direction of propagation of the wave is:

An electromagnetic wave with angular frequency $\omega$ and wavelength $\lambda$ propagates in the $+y$ direction. Its magnetic field is directed along the $-x$ direction. The vector expression for the associated electric field (with amplitude $E_0$) is ...........