Refraction occurs when waves travel from one transparent medium to another, causing a change in wave speed and direction.

The normal is an imaginary line drawn at 90° to a surface.

The angle of incidence is the angle between the incident ray and the normal.

The angle of refraction is the angle between the refracted ray and the normal.

Refraction through a rectangular block

Combined science

In A-level physics, some pupils will build on this knowledge to learn about the photon model of electromagnetic radiation and the use of electromagnetic radiation for collecting evidence about the universe or for generating images of the inside of a human body.

In the Measuring waves unit, pupils learnt about the measurable features of a wave, the relationship between them and the wave equation.

Electromagnetic waves

Physical activity and equipment requiring safe use

Which of the following words describe what can happen when light hits an object?

a wave splitting when it meets a boundary

a wave changing direction when it crosses a boundary

a wave changing direction by bouncing back from a boundary

The ray diagram represents a light wave passing from one medium to another. The normal is drawn as a dashed line. A student has placed a protractor over the diagram. What is the angle of refraction?

The angle of refraction is less than the angle of incidence.

The angle of refraction is greater than the angle of incidence.

When the ray crosses the boundary, it bends towards the normal.

When the ray crosses the boundary, it bends away from the normal.

The ray diagram shows the refraction of a light wave when it crosses a boundary between two materials. Which of these statements are correct?

The angle of refraction is always smaller than the angle of incidence.

The greater the angle of incidence, the greater the angle of refraction.

When the angle of incidence doubles, the angle of refraction doubles.

The angle of refraction increases by the same amount as the angle of incidence.

A student measures the angle of incidence and the angle of refraction at a boundary from air into a transparent block. The table shows the results. Which of these statements are correct?

Which of these ray diagrams shows a possible path of a ray through a plastic block?

What is represented by an arrow in a ray diagram?

A ray box produces a single ray of light.

Light can only reflect from shiny surfaces.

Which of the following statements about light is correct?

taken in and loses energy inside the material of the object

passes through the material of the object

Match the key words (relating to how light interacts with different objects) to their definitions.

In a ray diagram, the ray that approaches a surface or boundary is called the {{}} ray.

The ray diagram shown represents a light wave hitting a mirror. 
Which of the following diagrams shows the normal line (represented by a dashed line) drawn correctly?

The ray diagram shown is for a light wave reflecting from a mirror. A student has placed a protractor over the diagram. 
What is the angle of incidence?

Content guidance

Risk assessment required - equipment

Adult supervision required

This lesson will be removed by end of Summer Term 2025.

Refraction through a rectangular block

Lesson outcome

Content guidance

This lesson will be removed by end of Summer Term 2025.