Question

If a polarizing filter reduces the intensity of polarized light to 50.0% of its original value, by how much are the electric and magnetic fields reduced?

a. Electric field reduced to 50.0%, Magnetic field remains unchanged
b. Both electric and magnetic fields are reduced to 50.0%
c. Electric field remains unchanged, Magnetic field reduced to 50.0%
d. Both electric and magnetic fields remain unchanged

Answer 1

The polarization filter reduces the electric field amplitude to approximately 70.7% of its original value, and since the magnetic field is proportional to the electric field, it is reduced by the same amount.

Step-by-step explanation:

When a polarizing filter reduces the intensity of polarized light to 50.0% of its original value, the electric field amplitude of the light wave is reduced by a factor of the square root of 0.5, because intensity is proportional to the square of the electric field amplitude. This means that the electric field amplitude is reduced to about 70.7% of its original value. The magnetic field is directly proportional to the electric field, so it is also reduced by the same factor.