An unpolarised beam of light of intensity $I_0$ falls on a single polaroid. The intensity of the emergent beam is

$I_0/2$

The correct answer is Option (1) → $I_0/2$

For unpolarised light passing through a single polaroid, the transmitted intensity is half of the incident intensity:

$I = \frac{I_0}{2}$

∴ Intensity of the emergent beam = I₀/2