Question

Plane polarised light is passed through a polaroid. On viewing through the polaroid; we find that when the polaroid is given one complete rotation about the direction of the light, one of the following is observed

• A. the intensity of light gradually decreases to zero and remains at zero
• B. the intensity of light gradually increases to a maximum and remains at maximum
• C. there is no change in intensity
• D. the intensity of light is twice maximum and twice zero

Answer 1

Answer: (D)

During rotation $ \rightarrow $
When $\theta =0^\circ $ Intensity goes to maximum
When $\theta =90^\circ $ Intensity becomes zero
When $\theta =180^\circ $ Intensity become maximum again
When $\theta =270^\circ $ Intensity again become zero.
Where $\theta $ is the angle of rotation.