Electric field in a plane electromagnetic wave is given by ${E}=50 \sin \left(500 {x}-10 \times 10^{10} {t}\right) \,{V} / {m}$ The velocity of electromagnetic wave in this medium is :

(Given ${C}=$ speed of light in vacuum)

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:

A charged particle oscillates about its mean equilibrium position with a frequency of $10^9\ Hz$. The electromagnetic waves produced:

The electric field of a plane electromagnetic wave varies with time of amplitude $2\, Vm^{-1}$ propagating along $z$ -axis. The average energy density of the magnetic field  (in $J\, m^{-3}$) is 

A particle of charge $q$ and mass $m$ is moving along the $x-$ axis with a velocity $v,$ and enters a region of electric field $E$ and magnetic field $B$ as shown in figures below. For which figure the net force on the charge may be zero :-

The electric field intensity produced by the radiation coming from a $100\, W$ bulb at a distance of $3\, m$ is $E$. The electric field intensity produced by the radiation coming from $60\, W$ at the same distance is $\sqrt{\frac{x}{5}} E$. Where the value of $x=......... .$