# Lesson Worksheet: Refraction of Light Physics • 9th Grade

In this worksheet, we will practice describing refraction as the speed and direction change of light when passing between media of different densities.

Q1:

A light ray traveling in water of refractive index 1.3 is incident on the flat surface of a plastic block with a refractive index of 1.6, traveling through the block at an angle of 45 degrees from the line normal to the surface. At what angle from the line normal to the surface does the incident ray strike the block? Answer to the nearest degree.

Q2:

A light ray traveling in water of refractive index 1.3 is incident on the flat surface of a plastic block with a refractive index of 1.7, hitting the surface at an angle of 45 degrees from the line normal to the surface. At what angle from the line normal to the surface does the refracted ray in the block travel? Answer to the nearest degree.

Q3:

A light ray traveling in water with a refractive index of 1.3 is incident on a flat boundary with air, hitting the boundary at an angle of 45 degrees from the line normal to the boundary. At what angle from the line normal to the boundary does the refracted ray in the air travel? Answer to the nearest degree.

Q4:

A light ray traveling in air is incident on the flat surface of a plastic block with a refractive index of 1.5, hitting the surface at an angle of 45 degrees from the line normal to it. At what angle from the line normal to the surface does the refracted ray in the block travel? Answer to the nearest degree.

Q5:

A light ray traveling in air is incident on the flat surface of a plastic block, hitting the surface at an angle of 45 degrees from the line normal to it. The refracted ray in the block travels at an angle of 33 degrees to the line normal to the surface. What is the refractive index of the plastic? Give your answer to one decimal place.

Q6:

When a light ray passes from a medium into a different medium of lower density, does the speed of the ray increase, decrease, or not change?

• ANot change
• BDecrease
• CIncrease

Q7:

When a light ray passes from a medium into a different medium of higher density, does the speed of the ray increase, decrease, or not change?

• BIncrease
• CNot change

Q8:

A ray of light traveling in oil is incident on a flat boundary with air, hitting the boundary at an angle of 45 degrees from the line normal to the boundary. The refracted ray in the air travels at an angle of 58 degrees to the line normal to the boundary. What is the refractive index of the oil? Give your answer to one decimal place.

Q9:

A light ray passes from air into a different material that has a refractive index of 1.6. The light ray moves at m/s in air. At what speed does the light ray move in the material? Give your answer in scientific notation.

• A m/s
• B m/s
• C m/s
• D m/s
• E m/s

Q10:

The diagram shows a light ray passing from air through a glass block. Which angle is the angle of refraction from air to glass?

• AAngle
• BAngle
• CAngle
• DAngle

Which angle is the angle of incidence from glass to air?

• AAngle
• BAngle
• CAngle
• DAngle

Which angle is the angle of incidence from air to glass?

• AAngle
• BAngle
• CAngle
• DAngle

Which angle is the angle of refraction from glass to air?

• AAngle
• BAngle
• CAngle
• DAngle