A linearly polarized red laser beam in air has an intensity of and a wavelength of
PHYSICS · Multi-part · AP · Physics 2: Algebra-based · Waves Sound and Physical Optics · Waves Sound and Physical Optics
Problem
A linearly polarized red laser beam in air has an intensity of 1.20×103W⋅m−2 and a wavelength of 620nm. The beam first passes through an ideal polarizing sheet whose transmission axis is at 45° to the beam’s polarization direction. The emerging light then enters water (n=1.33) at normal incidence.
Ignore absorption or reflection losses at the air–water interface.
(a) Calculate the intensity of the light immediately after it passes through the polarizing sheet.
(b) Determine the wavelength of the light while it is propagating in the water.
(c) State the frequency of the light in the water and justify your answer based on wave principles.