## Refraction of light

### 1

Which of the statements below best describes the refractive index of a material?

### 2

How does the refractive index of air compare to the refractive index of empty space (vacuum)?

### 3

How does the refractive index of a material relate to the speed of light?

### 4

What is the effect on wavelength when light enters a material from air?

### 5

How does the refractive index of a material change with the frequency of light passing through it?

### 6

A student is investigating the effect that a semi-circular plastic block has on a ray of blue light (see the diagram below).

The student notes that when the angle of incidence inside the plastic is the angle of refraction in air is .

Calculate the refractive index of the plastic for the blue light.

### 7

Calculate the critical angle of the plastic for the blue light.

### 8

Which of the following statements is true for total internal reflection?

### 9

A ray of red light is incident on a triangular prism made from clear plastic (as shown in the diagram below).

The refractive index of the plastic is 1.46 for the red light.

Calculate the angle of refraction as the ray of red light leaves the prism.

This is a challenging “A grade” question requiring problem solving as well as subject knowledge.

### 10

Which diagram correctly identifies angles of incidence and refraction at a boundary between air and glass?