Practice Refraction in Physics

Use these practice problems to test your method after reviewing the concept explanation and worked examples.

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Quick Recap

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

A straw looks bent in a glass of water because light bends at the surface.

Showing a random 20 of 50 problems.

Example 1

easy
When light refracts into a new medium, which stays the same: frequency or wavelength?

Example 2

challenge
Find the critical angle for total internal reflection at a glass-air boundary, nglass=1.5n_{glass} = 1.5, nair=1n_{air} = 1.

Example 3

hard
Light enters a diamond (n=2.42n = 2.42) from air (n=1.00n = 1.00) at an angle of incidence of 45°45°. Find the angle of refraction. Then calculate the critical angle for light leaving diamond into air.

Example 4

medium
Light travels from water (n=1.33n = 1.33) into air (n=1.0n = 1.0) at an angle of incidence of 30°30°. What is the angle of refraction?

Example 5

medium
A medium has light speed v=1.5×108v = 1.5\times10^8 m/s. Find its refractive index (use c=3×108c = 3\times10^8 m/s).

Example 6

easy
The speed of light in a medium is 2.0×108 m/s2.0 \times 10^8 \text{ m/s}. What is the medium's refractive index?

Example 7

medium
Light enters a glass slab (n=1.5n = 1.5) at 60°60° from the normal. Find the angle inside the glass and verify it leaves the parallel exit face at 60°60°.

Example 8

challenge
A ray enters a glass slab (n=1.5n = 1.5) from air at θ1=45∘\theta_1 = 45^\circ, then exits the parallel far side back into air. What is the exit angle relative to the original direction?

Example 9

easy
Light passes from air (n=1.00n = 1.00) into water (n=1.33n = 1.33) at 45°45° from the normal. Find the angle of refraction.

Example 10

medium
Light slows from 3×1083\times10^8 m/s in vacuum to 2.4×1082.4\times10^8 m/s in a plastic. Find the plastic's refractive index.

Example 11

easy
When light goes from a low-index medium to a high-index medium, it bends ___ the normal.

Example 12

medium
Light of wavelength 600600 nm in vacuum enters glass with n=1.5n = 1.5. Find its wavelength in the glass.

Example 13

hard
A light ray hits the top of a glass cube (n=1.5n = 1.5) at 40°40° from the normal. What is the angle the refracted ray makes with the vertical (axis of the cube)?

Example 14

medium
Light goes from medium A (n=1.2n = 1.2) to medium B (n=1.6n = 1.6) at 50°50° to normal. Find the refraction angle.

Example 15

medium
Light goes from glass (n1=1.5n_1 = 1.5) into air (n2=1n_2 = 1) at θ1=30∘\theta_1 = 30^\circ. Find sin⁡(θ2)\sin(\theta_2).

Example 16

medium
Find the critical angle for light going from water (n=1.33n = 1.33) into air.

Example 17

easy
A ray normally incident on a flat glass surface refracts at what angle?

Example 18

easy
Why does a straw in a glass of water appear bent?

Example 19

easy
If n1sin⁡θ1=n2sin⁡θ2n_1 \sin\theta_1 = n_2 \sin\theta_2 and n2>n1n_2 > n_1, then θ2\theta_2 is ___ than θ1\theta_1.

Example 20

medium
Light hits a glass-air interface from the glass side (n=1.5n = 1.5) at 30°30°. Find the angle of refraction in air.
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