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The angle between the axes of two polarizing filters is 45.0º. By how much does the second filter reduce the intensity of the light coming through the first?

a) No reduction
b) 25.0% reduction
c) 50.0% reduction
d) 75.0% reduction

1 Answer

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Final answer:

When passing through two polarizing filters at an angle of 45.0°, the second filter reduces the intensity of light to 50.0% of its original intensity after the first filter.

Step-by-step explanation:

The question at hand deals with the effects of polarization on the intensity of light as it passes through polarizing filters. When unpolarized light passes through a polarizing filter, it becomes polarized, with the oscillations occurring only in a single plane. According to Malus's Law, when polarized light then passes through a second polarizing filter with an axis at an angle θ to the initial polarization direction, the intensity I of the light after passing through the second filter is I = I0cos2(θ), where I0 is the initial intensity of the polarized light after the first filter.

Given the angle between the axes of two polarizing filters is 45.0°, to find the reduction, we use θ = 45°. The intensity reduction is then given by I = I0cos2(45°) = I0(1/√2)2 = I0/2, which means the intensity is halved or reduced by 50.0%.

User Lyle Pratt
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