32. Electromagnetic Waves

What is the total energy density in an electromagnetic wave of intensity 1000 W/m²?

Consider current I passing through a resistor of radius r, length L, and resistance R. Determine the strength and direction of the Poynting vector at the surface of the resistor.

A microwave beam with a wavelength of 1.5 cm has an intensity of 25 W/m². What is the magnetic field amplitude?

At one instant, the electric and magnetic fields at one point of an electromagnetic wave are $\overrightarrow{E}=(200\hat{i}+300\hat{j}-50\hat{k})\text{ V/m}$ and $\overrightarrow{B}=B_0(7.3\hat{i}-7.3\hat{j}+a\hat{k})\mu \text{T}$. What are the values of $a$ and $B_0$?