The wavelengths of AM radio waves are so long—more than 200 m—that it would be impractical to make a (1)/(4) wavelength antenna to detect their electric field. Instead, AM radios detect the magnetic field of the wave using a coil of wire. The changing flux of the wave’s magnetic field induces an emf in the coil that is detected and amplified by the receiver. If you are standing to the west of an AM station that is broadcasting a vertically polarized wave, in which direction should the axis of the coil be oriented in order to best detect the wave?

We are keeping track of the electric field of an electromagnetic wave, and we note when the electric field is at half of its peak magnitude. What can we say about the magnitude of the magnetic field of the wave?

A 50 mW laser beam is polarized horizontally. It then passes through two polarizers. The axis of the first polarizer is oriented at 30° from the horizontal, and that of the second is oriented at 60° from the horizontal. What is the power of the transmitted beam?

Polarizers: Three polarizers with different axes of transmission will be placed in the path of an unpolarized laser beam with an intensity of 1000 W/m². The transmission axis of polarizer A is vertical (0°), that of B is rotated 35.5° clockwise with respect to vertical, and that of C is rotated 53.3° clockwise with respect to vertical. The polarizers can be placed in any order, but the second polarizer must be 522 mm from the first, and the third must be 229 mm from the second. (a) Find the arrangement of polarizers that maximizes the transmitted intensity and compute the maximum intensity. (b) Find the arrangement of polarizers that minimizes the transmitted intensity and compute the minimum intensity.

To maximize the magnitude of the current induced in a receiving antenna, should the antenna be oriented parallel or perpendicular to the polarization of the electromagnetic wave? Explain your reasoning.

The E field in an EM wave in free space has a peak of 20.7 mV/m. What is the average rate at which this wave carries energy across unit area per unit time? Express your answer using three significant figures.