# A polarizer-analyzer set is adjusted such that the intensity of light coming out of the analyzer is just 10 % of the original intensity.

A polarizer-analyzer set is adjusted such that the intensity of light coming out of the analyzer is just 10 % of the original intensity. Assuming that the polarizer-analyzer set does not absorb any light, the angle by which the analyser need to be rotated further to reduce the output intensity to be zero is

1. a. 45o
2. b. 90o
3. c. 71.6o
4. d. 18.4o

## 1 Answer

verified
Correct Answer is option D } 18o

Intensity after polarisation through polaroid = Iocos2φ

So, 0.1Io = Iocos2φ

⇒cosφ = √0.1

⇒cosφ = 0.316

Since, cos φ < cos 45o therefore, φ > 45o If the light is passing at 90o from the plane of polaroid, than its intensity will be zero.

Then, θ = 90o − φ therefore, θ will be less than 45o. So, the only option matching is option d which is 18.4o