A linearly polarized electromagnetic wave has an average intensity of 352 W/m 2

Question

A linearly polarized electromagnetic wave has an average intensity of 352 W/m2. This wave is directed towards two ideal polarizers (in real polarizers, transmission is also effected by reflection and absorption). Polarizer A is oriented with its transmission axis at an angle of 1 = 34.6° with the incident electric field. Polarizer B has its axis at an angle of 2 = 67.8° with the incident electric field, as shown in the figure.

What is the average intensity of the wave after it passes through polarizer A?


What is the average intensity of the wave after it passes through polarizer B?

Suppose that the two polarizers A and B are interchanged. What would the average intensity be after passing through both polarizers?

Explanation / Answer

given data

intensity of 352 W/m2.

1 = 34.6°

2 = 67.8°

A)

Use Malus's Law so after polarizer A

I = I0*cos^2 (34.6)

= 352W/m^2 *cos^2(34.6) = 238.5 W/m^2

B) After B (note here the angle is 67.8-34.6 = 33.2)

So IB = IA*cos^2(33.2) = 238.5*cos^2(33.2) = 167W/m^2


C) Here we have IB = I0*cos^2(67.8)*cos^2(33.2) = 352*cos^2(67.8)*cos^2(33.2) = 35.2W/m^2

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