Question

Unpolarized light passes through two ideal Polaroid sheets. The axis of the first is vertical and the axis of the second is at 40.0° to the vertical. What fraction of the incident light is transmitted?

Answer 1

When Unpolarized light passes through first polarizer, it's intensity will be reduced to half

I1 = I0/2

After that when light passes thorugh 2nd polarizer, Intensity will be given by Malus's law, So

I2 = I1*(cos A1)^2

I2 = (I0/2)*(cos A1)^2

A1 = angle between polaroid sheets = 40.0 deg

I2/I0 = (1/2)*(cos 40 deg)^2

I2 = 0.2934*I0

I2/I0 = 0.2934 (in fraction form)

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