Question

Sunlight passes through a couple of polarizers. If the transmitted brightness is 20% of the sunlight brightness, calculate the angle, rounded to the nearest tens of degrees, between the polarizers. A. 20° B. 30° OC. 40 D. 50° E. 60°

Answer 1

option D= 50°

Step-by-step explanation:

When sunlight passes through the first polarizer, the intensity reduces to its half

that is
`I_1=0.5I_o`.........(1)

let the angle between the polarizers be θ

then we know that the intensity of light after passing through second polarizer is

`I_2=I_1 cos\theta`

⇒
`I_2= 0.5I_o cos^2\theta`............(2) from (1)

also given that
`I_2=0.2I_o`..............(3)

equating 2 and 3 we get

`0.2I_o=0.5I_ocos^2\theta`

on solving the above equation we get

θ= 50.75°≅50°

hence the angle between polarizers is 50°

option D is correct