Refraction Physics Example 2

Follow the full solution, then compare it with the other examples linked below.

Example 2

hard
What is the critical angle for light going from glass (n=1.5n = 1.5) to air (n=1.0n = 1.0)?

Solution

  1. 1
    At the critical angle, the refracted ray travels along the surface (θ2=90°\theta_2 = 90°).
  2. 2
    n1sin⁡θc=n2sin⁡90°n_1 \sin\theta_c = n_2 \sin 90°
  3. 3
    1.5sin⁡θc=1.0  ⟹  sin⁡θc=11.5=0.6671.5 \sin\theta_c = 1.0 \implies \sin\theta_c = \frac{1}{1.5} = 0.667
  4. 4
    θc=sin⁡−1(0.667)≈41.8°\theta_c = \sin^{-1}(0.667) \approx 41.8°

Answer

θc≈41.8°\theta_c \approx 41.8°
The critical angle is the angle of incidence above which total internal reflection occurs. It only exists when light travels from a denser to a less dense medium.

About Refraction

The change in direction of a wave as it passes from one medium into another where it travels at a different speed.

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More Refraction Examples

Example 1 medium

Light passes from air ([formula]) into glass ([formula]) at an angle of incidence of [formula]. What

Example 3 medium

Light travels from water ([formula]) into air ([formula]) at an angle of incidence of [formula]. Wha

Example 4 hard

Light enters a diamond ([formula]) from air ([formula]) at an angle of incidence of [formula]. Find

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