wiz-icon
MyQuestionIcon
MyQuestionIcon
1
You visited us 1 times! Enjoying our articles? Unlock Full Access!
Question

Unpolarized light of intensity I passes through an ideal polarizer A. Another identical polarizer B is placed behind A. The intensity of light beyond B is found to be I2. Now another identical polarizer C is placed between A and B. The intensity beyond B is now found to be I8. The angle between polarizer A and C is:


A

45°

Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
B

60°

No worries! We‘ve got your back. Try BYJU‘S free classes today!
C

0°

No worries! We‘ve got your back. Try BYJU‘S free classes today!
D

30°

No worries! We‘ve got your back. Try BYJU‘S free classes today!
Open in App
Solution

The correct option is A

45°


Step 1: Given

The initial intensity of light: I

The intensity of light after A: I1=I2

The intensity of light after B: I2=I2

The intensity of light after B when C is also placed: I3=I8

image

Step 2: Formula Used

Malus Law Formula: I=I0cos2θ

Step 3: Find the angle between A and C

When light passes through a polariser its intensity becomes half. Here, when the light passes through A its intensity becomes half and again when it passes through B its intensity remains same as after passing through A. This implies that A and B are parallel to each other. Now, find an expression after light passes through C using Malus law.

IafterC=I1cos2θ=I2cos2θ

Calculate the value of angle using Malus law and substituting values

I3=IafterCcos2θI8=I2cos2θcos2θcos4θ=14cosθ=12θ=45°

Hence, the angle between polariser A and C is 45°.


flag
Suggest Corrections
thumbs-up
12
Join BYJU'S Learning Program
similar_icon
Related Videos
thumbnail
lock
Polarization II
PHYSICS
Watch in App
Join BYJU'S Learning Program
CrossIcon