Suppose that the intensity of a laser is $\left(\frac{315}{\pi}\right) \ W/m^2$. The $rms$ electric field,in units of $V/m$,associated with this source is close to the nearest integer. Given: $\epsilon_0 = 8.86 \times 10^{-12} \ C^2 N^{-1} m^{-2}$ and $c = 3 \times 10^8 \ m/s$.

In an electromagnetic wave,the energy density associated with the magnetic field will be:

An electromagnetic wave,going through vacuum,is described by $E = E_0 \sin(kx - \omega t)$. Which of the following is independent of wavelength?

All electromagnetic waves transport energy in the negative $z$ direction. At a certain point and time,the direction of the electric field of the wave is along the positive $y$ direction. What will be the direction of the magnetic field of the wave at that point and instant?

When an electromagnetic wave enters the ionized layer of the ionosphere,the relative permittivity of the ionized layer is found to be:

You are driving in your car listening to music on the radio. Your car is equipped with a radio that can receive radio signals of frequency $(f_1 \approx 3 \, MHz)$,$(f_2 \approx 30 \, MHz)$,and $(f_3 = 3 \, GHz)$. You enter a tunnel with a circular opening of diameter $10 \, m$. Which kind of radio signal will you be able to receive for the longest distance as you continue to travel in the tunnel?