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What is the critical angle for green light?

Published in Physics 2 mins read

The critical angle for green light depends on the materials involved in the refraction. It's not a single, universal value.

Here's why:

  • Refraction: When light travels from one medium to another (like air to water), it bends. This bending is called refraction, and the amount of bending depends on the angle of incidence and the refractive indices of the two materials.
  • Critical Angle: The critical angle is the specific angle of incidence at which the refracted light ray travels along the boundary between the two materials. This occurs when the angle of refraction is 90 degrees.
  • Refractive Index: Each material has a unique refractive index, which measures how much light bends when passing through it. Green light has a specific wavelength, and its refractive index will vary slightly depending on the material.

To calculate the critical angle for green light, you need to know the refractive indices of the two materials involved. You can then use Snell's Law:

sin(critical angle) = n2/n1

where:

  • n1 is the refractive index of the first material (the one where the light originates)
  • n2 is the refractive index of the second material (the one where the light is refracted)

Example:

Let's say green light is traveling from air (n1 = 1.00) to water (n2 = 1.33). Using Snell's Law:

  • sin(critical angle) = 1.33/1.00
  • critical angle = arcsin(1.33/1.00) ≈ 48.6 degrees

This means that if green light is traveling from air to water at an angle greater than 48.6 degrees, it will be totally reflected back into the air.

In summary:

The critical angle for green light depends on the refractive indices of the two materials involved and can be calculated using Snell's Law.

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