Physics

Physics

Problem

Horizontally polarized light of intensity I0I_0 strikes a single polarizing sheet whose transmission axis is 60° from the horizontal. Which expression gives the intensity of the transmitted light? a) 0.75 I00.75\,I_0 b) 0.50 I00.50\,I_0 c) 0.25 I00.25\,I_0 d) 0.125 I00.125\,I_0
Intuitive explanation

When polarized light passes through a polarizer, Malus's Law tells you that the transmitted intensity depends on the angle between the incident polarization direction and the polarizer's transmission axis. The key is recognizing that intensity scales with the square of the cosine of this angle—not the angle itself. Here, your incident light is horizontal and the polarizer is tilted 60° away, so you need to find I0cos⁡2(60°)I_0 \cos^2(60°).

Intuitive explanation

When polarized light passes through a polarizer, Malus's Law tells you that the transmitted intensity depends on the angle between the incident polarization direction and the polarizer's transmission axis. The key is recognizing that intensity scales with the square of the cosine of this angle—not the angle itself. Here, your incident light is horizontal and the polarizer is tilted 60° away, so you need to find I0cos⁡2(60°)I_0 \cos^2(60°).

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