1
You visited us 1 times! Enjoying our articles? Unlock Full Access!
Question

# Unpolarized light of intensity 32 W m−2 passes through three polarizers such that transmission axis of first is crossed with third. If the intensity of emerging light is 2 W m−2, what is the angle between the transmission axes of the first two polarizers?

A
30
No worries! We‘ve got your back. Try BYJU‘S free classes today!
B
60
No worries! We‘ve got your back. Try BYJU‘S free classes today!
C
22.5
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
D
45
No worries! We‘ve got your back. Try BYJU‘S free classes today!
Open in App
Solution

## The correct option is C 22.5∘The transmission axis of the first polarizer is crossed with the third. Let θ be the angle between the axis of the first two polarizers then the angle between 2nd and 3rd polarizers will be (90∘−θ). Let I0 is the intensity of the unpolarized light incident on the first polarizer. The intensity of light emerging from first polarizer is, I1=I02 According to Malu's law, The intensity of light emerging from second polarizer is, I2=I02 cos2θ And, The intensity of light emerging from third polarizer is, I=(I02)cos2θcos2(90∘−θ) ∴2=322cos2θcos2(90∘−θ) 2=16cos2θsin2θ 12=4cos2θsin2θ (2sinθcosθ)2=12 sin2 2θ=12 ∴sin2θ=1√2 And, 2θ=45∘ ⇒θ=22.5∘ Hence, (C) is the correct answer.

Suggest Corrections
1
Join BYJU'S Learning Program
Related Videos
Polarization II
PHYSICS
Watch in App
Explore more
Join BYJU'S Learning Program