# Polarizing Sunglasses physics problem

1. Apr 6, 2005

### stunner5000pt

Sunlight illuminates a 2mm hole in the blinds and falls on Polarizing Sunglasses. A plastic linear polarizer is placed (between the blinds and the sunglasses) ahead of the sunglasses with the lines aligned horizontally at time = 0. At this time the polarizer is rotated in a clockwise direction at a rate of 360 degrees per second.The sunlight has lambda ranges between 400nm and 700nm and intensity of 1kW/m^2.

a) after 0.5 seconds will the light that passes through the polairzer be half right hand circular polarized? Explain what the polarization will be as a function of time

well since it is rotated at 360 degrees for second after 180 degrees half of the beam has been polarized (right?) Would this be a sinusoidal function??

b) as a function of times plot the intensity and power of the light that falls on the sunglasses
would hte intensity be a constant function??
Wouldnt the power too be a constant function??

c) Plot the intensitry of the light that makes it through the glasses
Wouldnt it be a constant function as well??

d) Write down the expression for the elctric field at time = 0.625s that reaches the sunglasses for the wavelength = 514nm.
after 0.625s the axis has covered 225 degrees so beta - alpha = 45 degrees

it isnt specified whether this is a half wave or quarter wave plate
would i use this formula
$$E = E_{0} [cos(\alpha) cos(\beta - \alpha) + sin(\alpha) sin(\beta-\alpha)]$$

and both alphab ad beta - alpha = 45 degrees or pi/4 radians?

What is the value for omega and k? omega = 2pi / T - 2pi / 1 = 2pi?
k = 2 pi / v but what is v? the speed of light?

im guessing that the polarizer used in a full wave or a half wave plate because a subsequent question starts using a quarter wave plate

Last edited: Apr 6, 2005