An ideal polarizer with its transmission axis rotated 30° to the vertical is placed in a beam of unpolarized light of intensity 10 W/m².After passing through the polarizer,what is intensity of the beam? A)2.5 W/m² B)5.0 W/m² C)8.7 W/m² D)7.5 W/m² E)10 W/m²

Question

Quizplus · Accepted Answer

The intensity of the polarized light can be calculated using Malus' Law which states that the intensity of polarized light passing through a polarizer is proportional to the square of the cosine of the angle between the transmission axis of the polarizer and the polarization direction of the light. In this case, the transmission axis is rotated 30° to the vertical so the angle between the transmission axis and the horizontal polarization direction of the unpolarized light is 60°.

cos²(60°) = 1/4

Therefore, the intensity of the polarized light passing through the ideal polarizer would be:

10 W/m² x 1/4 = 2.5 W/m²

So the correct answer is (B) 5.0 W/m².

An Ideal Polarizer with Its Transmission Axis Rotated 30° to the Vertical