Practice Total Internal Reflection in Physics

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

Worksheet PDF Free Answer-key PDF Family

Quick Recap

Total internal reflection happens when light traveling in a higher-index medium hits a boundary to a lower-index medium at an angle greater than the critical.

At a steep enough angle, light gets trapped and bounces inside the material.

Showing a random 20 of 50 problems.

Example 1

easy
A material has critical angle θc\theta_c to air given by sin⁡θc=0.5\sin\theta_c = 0.5. Find θc\theta_c.

Example 2

easy
Why does a film of water on a windshield reduce the critical angle for light traveling from glass into the wet windshield surface?

Example 3

easy
True or false: TIR happens whenever the angle of incidence equals the critical angle exactly.

Example 4

medium
Light in a medium with n1=1.6n_1 = 1.6 meets a boundary to a medium with n2=1.4n_2 = 1.4 at 65∘65^\circ. Does TIR occur?

Example 5

easy
For total internal reflection to occur, light must travel from a medium with which index toward which?

Example 6

medium
Light in glass (n=1.5n=1.5) hits the boundary to water (n=1.33n=1.33). Find the critical angle.

Example 7

easy
Find the critical angle for light going from water (n1=1.33n_1=1.33) to air (n2=1.0n_2=1.0).

Example 8

medium
In optical fiber communication, why is TIR preferred over a metallic mirror coating?

Example 9

easy
Light in glass hits the glass-air boundary at an angle greater than the critical angle. What happens?

Example 10

hard
A swimmer underwater shines a laser upward. As she tilts the beam from vertical, at what tilt (relative to vertical) does the beam stop emerging into the air? (nwater=1.33n_{\text{water}} = 1.33)

Example 11

medium
A glass with n=1.5n = 1.5 is coated with a film of n=1.7n = 1.7. For light inside the glass hitting the interface, can TIR occur there?

Example 12

medium
Find the critical angle for light passing from a glass with n1=1.75n_1 = 1.75 into air.

Example 13

easy
Find the critical angle for light going from glass (n1=1.5n_1=1.5) to air (n2=1.0n_2=1.0).

Example 14

easy
Can total internal reflection occur for light going from air into water?

Example 15

medium
A 45-45-90 prism is used to turn light by 90 degrees using TIR. The glass has n=1.5n=1.5. The light hits the hypotenuse face at 45∘45^\circ. Does TIR occur there?

Example 16

medium
Light in water (n=1.33n=1.33) hits the water-air surface at 50∘50^\circ. The critical angle is about 48.8∘48.8^\circ. Does TIR occur?

Example 17

medium
Light in glass (n=1.5n=1.5) hits a glass-air boundary at 30∘30^\circ (below the 41.8∘41.8^\circ critical angle). What happens to the light?

Example 18

medium
A right-angle prism (n=1.52n=1.52) is used as a periscope element. Light enters the long face normally and hits the hypotenuse at 45∘45^\circ. Does it TIR off the hypotenuse?

Example 19

medium
A diver looks straight up from underwater. Light from the sky reaches the diver from a circular 'window'. What is the half-angle (in water) of that window? (nwater=1.33n_{\text{water}} = 1.33)

Example 20

medium
A glass core (n1=1.50n_1 = 1.50) is surrounded by cladding (n2=1.45n_2 = 1.45). Find the critical angle at the core-cladding boundary.
← Back to Total Internal Reflection Worked Examples Formula Explained

Related Concepts

RefractionLenses