About $5 \%$ of the power of a $100\; W$ light bulb is converted to visible radiation. What is the average intensity of visible radiation

$(a)$ at a distance of $1 \;m$ from the bulb?

$(b)$ at a distance of $10\; m ?$ Assume that the radiation is emitted isotropically and neglect reflection.

The electric fields of two plane electromagnetic plane waves in vacuum are given by

$\overrightarrow{\mathrm{E}}_{1}=\mathrm{E}_{0} \hat{\mathrm{j}} \cos (\omega \mathrm{t}-\mathrm{kx})$ and

$\overrightarrow{\mathrm{E}}_{2}=\mathrm{E}_{0} \hat{\mathrm{k}} \cos (\omega \mathrm{t}-\mathrm{ky})$

At $t=0,$ a particle of charge $q$ is at origin with a velocity $\overrightarrow{\mathrm{v}}=0.8 \mathrm{c} \hat{\mathrm{j}}$ ($c$ is the speed of light in vacuum). The instantaneous force experienced by the particle is 

Which of the following statement is true for displacement current

Consider an electromagnetic wave propagating in vacuum . Choose the correct statement

An electromagnetic wave travels along $z-$axis. Which of the following pairs of space and time varying fields would generate such a wave