The velocity of an electromagnetic wave in a medium is $2.5 \times 10^{8} \ m/s$. What is the dielectric constant of the medium?

Which of the following statements is false regarding the properties of electromagnetic waves?

$A$ laser beam has an intensity of $4.0 \times 10^{14} \ W/m^{2}$. The amplitude of the magnetic field associated with the beam is . . . . . . $T$. (Take $\epsilon_{0} = 8.85 \times 10^{-12} \ C^{2}/Nm^{2}$ and $c = 3 \times 10^{8} \ m/s$)

The electric field for a plane electromagnetic wave travelling in the $+y$ direction is shown. Consider a point where $\vec E$ is in the $+z$ direction. The $\vec B$ field is

An electron is constrained to move along the $y$-axis with a speed of $0.1 c$ ($c$ is the speed of light) in the presence of an electromagnetic wave,whose electric field is $\overrightarrow{E} = 30 \hat{j} \sin(1.5 \times 10^7 t - 5 \times 10^{-2} x) \, V/m$. The maximum magnetic force experienced by the electron will be: (given $c = 3 \times 10^8 \, m/s$ and electron charge $q = 1.6 \times 10^{-19} \, C$)

$A$ point source of electromagnetic radiation has an average power output of $800\,W$. The maximum value of the electric field at a distance of $3.5\,m$ from the source will be.....$V/m$.