Starter quiz
- When a wave bounces back from a surface or boundary, this is called ______.
- 'reflection' ✓
- Which of the following types of material transmit light?
- opaque
- translucent ✓
- transparent ✓
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- Which of the following statements describe a light ray?
- It is not a real thing. ✓
- It is produced by a laser.
- It is produced by a ray box.
- It is a way of modelling light. ✓
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- Which of the following describe the normal in a ray diagram for reflection?
- It is drawn parallel to the mirror.
- It is drawn at right angles to the mirror. ✓
- It is useful for measuring angles on a ray diagram. ✓
- It is useful for measuring distances on a ray diagram.
- It meets the mirror where the ray meets the mirror. ✓
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- A representation of an object seen where light appears to come from, not where light actually comes from, is called a ______ image.
- 'virtual' ✓
- Which of the following best describes the conclusion of an experiment?
- a list of ways to improve the experiment
- a table and graph of the measurements made
- a statement of what was discovered, and how it is known ✓
- a description of the equipment used and the steps taken
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Exit quiz
- Which of the following is a definition of ‘medium’?
- a single light ray
- a collection of light rays
- a material that light reflects from
- a boundary between two materials
- a material that light is travelling through ✓
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- Which of the following is a definition of ‘refraction’?
- the opposite of reflection
- the opposite of transmission
- a change in colour when light enters a new material
- a change in direction when light enters a new material ✓
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- Which of the following are possible when light hits a boundary between two materials?
- transmission without refraction ✓
- refraction without transmission
- both transmission and refraction ✓
- neither transmission nor refraction ✓
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- An incident ray hits a boundary between air and glass. There is no refraction if the angle of incidence is...
- 0°. ✓
- 45°.
- 90°.
- 180°.
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The diagram shows three light rays entering a block of glass. Which of the following statements are correct?- Ray A is refracted least.
- Ray C is refracted least. ✓
- All three rays are bent towards the normal. ✓
- All three rays are bent away from the normal.
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- Which of the following diagrams show possible paths of light rays passing through transparent rectangular blocks?
Worksheet
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Presentation
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Video
Lesson Details
Key learning points
- Light changes direction when it moves into a new medium (material) at an angle to the normal. This is called refraction.
- When light enters a transparent material from air, it turns towards the normal.
- When light leaves a transparent material and re–enters air it turns away from the normal.
- A ray that enters and leaves glass through parallel sides ends up in its original direction, but displaced to the side.
- Refraction can cause virtual images of objects to appear where light seems to be coming from.
Common misconception
A ray of light curves as it passes through glass, perspex or water.
Use a perspex block with the bottom painted white to demonstrate the path of a ray of light through it. Avoid putting too much emphasis on the term 'bending' light, instead try to primarily refer to light changing direction at a boundary.
Keywords
Transmit - when light moves into and through a new medium
Medium - the material that light is travelling through
Refraction - when light changes direction when it enters a new medium
Normal - a line drawn at 90° to the surface of a material
Virtual image - a representation of an object seen where light appears to be coming from, not where light actually comes from
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