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Refraction and refractive index

  • 3 things to know
  • Papers 2 and 3

Overview

Recall questions on refraction and refractive index, n = c/v, the direction light bends between media, investigating refraction with rectangular and semi-circular blocks, and Snell's law.

What you need to know

Answer each one before you reveal it.

Your recallNot started
Who and when

What quantity remains constant when light crosses a boundary between two media, according to the relationship involving refractive index and angle?

Key term

Define refraction.

Key term

Write the rearranged form of Snell's law used to find the angle of refraction.

Questions from this subtopic

Each one with the model answer underneath.

  1. 1

    Define refraction.

    Model answer

    The change in direction of a wave when it passes from one medium to another due to a change in wave speed.

  2. 2

    How is the refractive index of a material defined?

    Model answer

    The ratio of the speed of light in a vacuum to the speed of light in the material.

  3. 3

    State the equation used to calculate the refractive index of a medium and define each symbol.

    Model answer

    n = c/v, where n is the refractive index, c is the speed of light in a vacuum, and v is the speed of light in the medium.

  4. 4

    Calculate the refractive index when speed of light in vacuum = 3.00 × 10⁸ m s⁻¹, speed of light in medium = 1.43 × 10⁸ m s⁻¹.

    Model answer

    Refractive index = (3.00 × 10⁸) ÷ (1.43 × 10⁸) = 2.10.

  5. 5

    In which direction does light bend when it travels from a less optically dense medium into a more optically dense medium?

    Model answer

    It bends towards the normal.

  6. 6

    What happens to the direction of a light ray when it passes from a more optically dense medium into a less optically dense medium?

    Model answer

    It bends away from the normal.

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