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Statement I: On viewing the clear blue portion of the sky through a Calcite Crystal, the intensity of transmitted light varies as the crystal is rotated.
Statement II: The light coming from the sky is polarized due to scattering of sun light by particles in the atmosphere. The scattering is largest for blue light.

Asked in JEE Main 2011 (Re-exam) · Malus's law and polaroids

• (1) Statement I is true, Statement II is false.
• (2) Statement I is true, Statement II is true, statement II is the correct explanation of statement I.
• (3) Statement I is true, Statement II is true, statement II is not the correct explanation of statement I.
• (4) Statement I is false, Statement II is true.

Step-by-step solution

Why the other options are wrong

• (1) Rejects Statement II, though scattered skylight is partially polarised and scattering ∝ 1/λ⁴ is largest for blue.
• (3) Misses that the polarisation by scattering is exactly why the transmitted intensity changes on rotating the crystal.
• (4) Rejects Statement I, forgetting that calcite acts as an analyser for polarised skylight.

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