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Ch 33: The Nature and Propagation of Light
Young & Freedman Calc - University Physics 15th Edition
Young & Freedman Calc15th EditionUniversity PhysicsISBN: 9780135159552당신이 사용하는 게 아니라요?교과서 변경
32장, 문제 27

Unpolarized light with intensity I0 is incident on two polarizing filters. The axis of the first filter makes an angle of 60.0° with the vertical, and the axis of the second filter is horizontal. What is the intensity of the light after it has passed through the second filter?

검증된 단계별 안내
1
Start by understanding that unpolarized light has an equal intensity in all directions. When it passes through the first polarizing filter, the intensity is reduced by half. Therefore, the intensity after the first filter is I1 = I0 / 2.
Next, apply Malus's Law to determine the intensity of light after it passes through the second polarizing filter. Malus's Law states that the intensity I after passing through a polarizer is given by I = I1 * cos^2(θ), where θ is the angle between the light's polarization direction and the axis of the polarizer.
In this problem, the angle θ between the light's polarization direction after the first filter (which is at 60.0° to the vertical) and the axis of the second filter (which is horizontal) is 90.0° - 60.0° = 30.0°.
Substitute the values into Malus's Law: I = (I0 / 2) * cos^2(30.0°).
Calculate cos(30.0°), which is √3/2, and then square it to find cos^2(30.0°). Substitute this value back into the equation to find the final intensity of the light after it passes through the second filter.

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주요 개념

질문에 올바르게 답하기 위해 반드시 이해해야 하는 핵심 개념들은 다음과 같습니다.

Unpolarized Light

Unpolarized light consists of waves vibrating in multiple planes perpendicular to the direction of propagation. When such light encounters a polarizing filter, it becomes polarized, meaning it vibrates in a single plane. The intensity of unpolarized light is reduced by half after passing through the first polarizer, as only the component aligned with the filter's axis is transmitted.
추천 영상:
가이드 코스
10:30
Ray Nature of Light

Malus's Law

Malus's Law describes how the intensity of polarized light changes as it passes through a second polarizing filter. The transmitted intensity I is given by I = I0 * cos²(θ), where I0 is the initial intensity and θ is the angle between the light's polarization direction and the filter's axis. This law is crucial for calculating the intensity after the second filter in the given problem.
추천 영상:
가이드 코스
09:47
Multiple Polarizers & Malus's Law

Polarization Angle

The polarization angle is the angle between the polarization direction of light and the axis of a polarizing filter. In the problem, the first filter is at 60° to the vertical, and the second is horizontal, making the effective angle between the polarized light from the first filter and the second filter's axis 30°. This angle is used in Malus's Law to determine the final intensity.
추천 영상:
가이드 코스
05:32
Introduction to Polarization
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