## Refraction Sample Problems

1. A light ray is incident on crown glass (n=1.52) at an angle of 30° to the normal. It is incident from air. What is the angle of refraction?
2. A ray of light falls on a lake surfaces at an angle of 35° to the surface of the water (n=1.33). Draw the incident and the reflected rays. Determine the magnitude of the reflected ray. Draw the refracted ray. Determine the magnitude of the refracted ray.
3. A light ray passes from air into an unknown substance. The incident angle is 23° and the refracted angle is 14°. What is the index of refraction of the unknown substance?
4. The index of refraction of water is 1.33. What is the speed of light in water?
5. The speed of light in a substance is 2.56 x 108m/s. What is the index of refraction of the substance?
6. What is the critical angle for a diamond (n=2.42) to air boundary?
7. What is the critical angle for a gemstone whose index of refraction is 1.86?

## Lenses Sample Problems

Describe the image mathematically and using a ray diagram. Find the magnification ratio. Always use a 1 cm high object.

1. An object is placed 30 cm in front of a convex lens with a 10 cm focal length.
2. An object is placed 10 cm in front of a convex lens with a 6 cm focal length.
3. An object is placed 5 cm in front of a convex lens with a 10 cm focal lenght.
4. An object is placed 15 cm in front of a concave lens with an 8 cm focal length.
5. An object is placed 3 cm in front of a concave lens with a 5 cm focal length.