Plane microwaves from a transmitter are directed normally towards a plane reflector. $A$ detector moves along the normal to the reflector. Between positions of $14$ successive maxima, the detector travels a distance $0.13\, m$. If the velocity of light is $3 \times 10^8 m/s$, find the frequency of the transmitter.

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

In an $E.M.$ wave the average energy density is associated with

A particle of mass $\mathrm{m}$ and charge $\mathrm{q}$ has an initial velocity $\overline{\mathrm{v}}=\mathrm{v}_{0} \hat{\mathrm{j}} .$ If an electric field $\overrightarrow{\mathrm{E}}=\mathrm{E}_{0} \hat{\mathrm{i}}$ and magnetic field $\overrightarrow{\mathrm{B}}=\mathrm{B}_{0} \hat{\mathrm{i}}$ act on the particle, its speed will double after a time:

An electric charge $+ q$ moves with velocity $\overrightarrow V  = 3\hat i + 4\hat j + \hat k$ in an electromagnetic field given by :  $\overrightarrow E  = 3\hat i + \hat j + 2\hat k$ and $\overrightarrow B  = \hat i + \hat j - 3\hat k$. The $y-$ component of the force experienced by $+ q$ is :-

If $E$ and $B$ denote electric and magnetic fields respectively, which of the following is dimensionless