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In the diagram below, linearly polarized light is polarized at an angle 30 degre

ID: 1409411 • Letter: I

Question

In the diagram below, linearly polarized light is polarized at an angle 30 degrees with the vertical shown by the dotted vertical line. The polarized light moves rightward and is incident on filter1 (P1) whose polarizing axis is vertical. The light then continues to travel rightward and goes through a second filter whose polarizing axis is 30 degrees with the vertical. Assume the intensity of the light before reaching P1 is I_o = 75.0 W/cm^2. What is the intensity of the light after it passes through PI but before it reaches P2? In what direction is the light polarized after it passes through PI but before it reaches P2? What is the intensity of the light after it passes through P2? In what direction is the light polarized after it passes through P2?

Explanation / Answer

Apply Malus law to calcualte the intensity of light

I = Io cos^2 theta

(a)

I1 = 75 cos^2 30 = 56.25 W/cm^2

(b) along y direction

(c)

I2 = I1 cos^2 theta

=  56.25 W/cm^2 cos^2 ( 360-30)

=42.18 W/cm^2

(d)

along y axis