Question

An unpolarised light of intensity \(64\text{ Wm}^{-2}\) passes through three polarizers successively such that the transmission axis of last polarizer is crossed with the first. The intensity of the emerging light is \(6\text{ Wm}^{-2}\). The angle between the transmission axis of the first two polarizers is

• A. \(\frac{1}{2}sin^{-1}(\frac{\sqrt{3}}{2})\)
• B. \(\frac{1}{2}cos^{-1}(\frac{\sqrt{3}}{2})\)
• C. \(\frac{1}{2}sin^{-1}(\frac{1}{\sqrt{3}})\)
• D. \(\frac{1}{2}cos^{-1}(\frac{1}{\sqrt{3}})\)

Hint:

The refractive index depends on wavelength, so different colours bend by different amounts.

Answer 1

The Correct Option is A

Step 1: Dispersion:
A prism splits white light because each colour is refracted through a different angle.

Step 2: Conclusion:
So the angle of refraction changes with colour (B).

Final Answer:
Option (B). \[ \boxed{\text{(B)}} \]