An unpolarised light of intensity I₀ passes through a polariser. The transmitted intensity is
A{'text': 'I₀', 'label': 'A'}
B{'text': 'I₀/4', 'label': 'B'}
C{'text': 'I₀/2', 'label': 'C'}
D{'text': '2 I₀', 'label': 'D'}
Answer & Solution
Correct answer: C. {'text': 'I₀/2', 'label': 'C'}
1. Unpolarised light contains all polarisation directions equally.
2. An ideal polariser transmits only one direction.
3. Averaged over all directions, transmitted intensity is half the incident: I = I₀/2.
4. This is the average over cos² θ around a full circle.
_Source: NCERT Class 12 Physics, Ch 10 "Wave Optics", §10.7_
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