Question

part and in parallel planes. The transmission axis of the second sheet is 33 ∘ relative to the first one. The transmission axis of the third sheet is 90∘relative to the first one. Unpolarized light impinges on the first polarizing sheet.

Part A

What percent of this light is transmitted out through the third polarizer?

Express your answer using two significant figures.

I₃/I0 ×100% =

  %  

Answer 1

when a perfect polarizer is placed in a polarized beam of light, the irradiance, I, of the light that passes through is given by

Malus'w

  

where I₀ is the initial intensity and θ_i is the angle between the light's initial polarization direction and the axis of the polarizer.

Now-

Let Intensity of light passing through first polariser was I₀

Then intensity of light passing through second polariser given by....

I_I = I₀ cos² 33 = I_o 0.7034

And intensity of light passing through third will be as it is at 90° relative to first then it is 57° relative to second polariser.

I_{2 =} I₁cos ² 57= 0.7034 I₀ (.2966)

hence I₂ = 0.2086 I₀

_{peecentage of light passing through third polariser will be}

0.2086 I₀ * 100/I₀ = 20.86 %

hence answer will be 21% having two significant figures.