Source: https://senecalearning.com/en-gb/revision-notes/gcse/science-practicals/national-curriculum/3-1-11-light-reflection-and-refraction

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# Light Reflection & Refraction

Science Practicals: GCSE, topic 3.1.11

## Reflection of Light

Light can be reflected by a plane (flat surface).

### Angle of incidence

![Angle of incidence](https://image-v2.cdn.app.senecalearning.com/courseImages/physics/3.1.1%20Changing%20Wave%20Motion/3.2.1.1%20-%20Reflection%20(concept%20-%20incidence)%20(1)-min.jpg)

- The angle of incidence is the angle between the incident (incoming) light ray and the normal.
- The normal is a line at 90 degrees to the plane.

### Angle of reflection

![Angle of reflection](https://image-v2.cdn.app.senecalearning.com/courseImages/physics/3.1.1%20Changing%20Wave%20Motion/3.2.1.1%20-%20Reflection%20(concept%20-%20reflected)-min.jpg)

- The angle of reflection is the angle between the reflected light ray and the normal.

### Law of reflection

![Law of reflection](https://image-v2.cdn.app.senecalearning.com/courseImages/physics/3.1.1%20Changing%20Wave%20Motion/3.2.1.1%20-%20Law%20of%20Reflection%20(concept%20-%20reflected)-min.jpg)

- The law of reflection states that the angle of incidence = the angle of reflection.

## Refraction of Light

Light is refracted when it travels from one medium to another and changes speed.

### Optically dense materials

![Optically dense materials](https://image-v2.cdn.app.senecalearning.com/courseImages/physics/3.1.1%20Changing%20Wave%20Motion/turtle-2902628_640-min.png)

- If light slows down as it enters a new medium, this medium is “more optically dense”.
- When light enters a more optically dense medium, it is refracted closer to the normal. 
- This means that the angle of refraction is smaller than the angle of incidence.

### Less optically dense materials

![Less optically dense materials](https://image-v2.cdn.app.senecalearning.com/courseImages/physics/3.1.1%20Changing%20Wave%20Motion/rabbit-2414356_640-min.jpg)

- If light speeds up on entering a new medium, this medium is “less optically dense”.
- The light is refracted further from the normal - the angle of refraction is larger than the angle of incidence.

## Angle of Refraction

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

### More optically dense material

![More optically dense material](https://image-v2.cdn.app.senecalearning.com/courseImages/physics/3.1.1%20Changing%20Wave%20Motion/turtle-2902628_640-min.png)

When light enters a more optically dense medium, it is refracted closer to the normal and the angle of refraction is smaller.

### Less optically dense

![Less optically dense](https://image-v2.cdn.app.senecalearning.com/courseImages/physics/3.1.1%20Changing%20Wave%20Motion/rabbit-2414356_640-min.jpg)

When light travels from one medium and to a less optically dense medium, it is refracted further away from the normal and the angle of refraction is larger.

## Test yourself on Light Reflection & Refraction

- What is the normal?
- What will happen to the angle of reflection if the angle of incidence increases?
- What will happen to the wave if the light enters a less optically dense material?
- What happens to light entering a material with higher optical density?
- What happens to a ray of light when it enters a more optically dense material?

[Practise this topic for free](https://app.senecalearning.com/classroom/course/35d9e7b0-1dfb-11e8-b5b7-7546c70e1a36/section/143938b8-0de4-4563-9616-489c1cae86f8/session)

- Previous topic: [3.1.10 Light](https://senecalearning.com/en-gb/revision-notes/gcse/science-practicals/national-curriculum/3-1-10-light.md)
- Next topic: [3.1.12 Radiation](https://senecalearning.com/en-gb/revision-notes/gcse/science-practicals/national-curriculum/3-1-12-radiation.md)

## Science Practicals: GCSE contents

### 1 Biology
- 1.1 Practicals
  - [1.1.1 Microscope & Bacteria](https://senecalearning.com/en-gb/revision-notes/gcse/science-practicals/national-curriculum/1-1-1-microscope-and-bacteria.md)
  - [1.1.2 Bacteria](https://senecalearning.com/en-gb/revision-notes/gcse/science-practicals/national-curriculum/1-1-2-bacteria.md)
  - [1.1.3 Osmosis Tests](https://senecalearning.com/en-gb/revision-notes/gcse/science-practicals/national-curriculum/1-1-3-osmosis-tests.md)
  - [1.1.4 Osmosis & Food Tests](https://senecalearning.com/en-gb/revision-notes/gcse/science-practicals/national-curriculum/1-1-4-osmosis-and-food-tests.md)
  - [1.1.5 Enzymes](https://senecalearning.com/en-gb/revision-notes/gcse/science-practicals/national-curriculum/1-1-5-enzymes.md)
  - [1.1.6 Enzymes 2](https://senecalearning.com/en-gb/revision-notes/gcse/science-practicals/national-curriculum/1-1-6-enzymes-2.md)
  - [1.1.7 Photosynthesis & Plant Responses](https://senecalearning.com/en-gb/revision-notes/gcse/science-practicals/national-curriculum/1-1-7-photosynthesis-and-plant-responses.md)
  - [1.1.8 Photosynthesis Experiments](https://senecalearning.com/en-gb/revision-notes/gcse/science-practicals/national-curriculum/1-1-8-photosynthesis-experiments.md)
  - [1.1.9 Reaction Time](https://senecalearning.com/en-gb/revision-notes/gcse/science-practicals/national-curriculum/1-1-9-reaction-time.md)
  - [1.1.10 Quadrats](https://senecalearning.com/en-gb/revision-notes/gcse/science-practicals/national-curriculum/1-1-10-quadrats.md)
  - [1.1.11 Decay](https://senecalearning.com/en-gb/revision-notes/gcse/science-practicals/national-curriculum/1-1-11-decay.md)

### 2 Chemistry
- 2.1 Practicals
  - [2.1.1 Salts](https://senecalearning.com/en-gb/revision-notes/gcse/science-practicals/national-curriculum/2-1-1-salts.md)
  - [2.1.2 Neutralisation](https://senecalearning.com/en-gb/revision-notes/gcse/science-practicals/national-curriculum/2-1-2-neutralisation.md)
  - [2.1.3 Titration](https://senecalearning.com/en-gb/revision-notes/gcse/science-practicals/national-curriculum/2-1-3-titration.md)
  - [2.1.4 Electrolysis](https://senecalearning.com/en-gb/revision-notes/gcse/science-practicals/national-curriculum/2-1-4-electrolysis.md)
  - [2.1.5 Electrolysis 2](https://senecalearning.com/en-gb/revision-notes/gcse/science-practicals/national-curriculum/2-1-5-electrolysis-2.md)
  - [2.1.6 Rate of Reaction](https://senecalearning.com/en-gb/revision-notes/gcse/science-practicals/national-curriculum/2-1-6-rate-of-reaction.md)
  - [2.1.7 Rate of Reaction 2](https://senecalearning.com/en-gb/revision-notes/gcse/science-practicals/national-curriculum/2-1-7-rate-of-reaction-2.md)
  - [2.1.8 Chromatography](https://senecalearning.com/en-gb/revision-notes/gcse/science-practicals/national-curriculum/2-1-8-chromatography.md)
  - [2.1.9 Identifying Gases](https://senecalearning.com/en-gb/revision-notes/gcse/science-practicals/national-curriculum/2-1-9-identifying-gases.md)
  - [2.1.10 Identifying Gases 2](https://senecalearning.com/en-gb/revision-notes/gcse/science-practicals/national-curriculum/2-1-10-identifying-gases-2.md)
  - [2.1.11 Identifying Ions](https://senecalearning.com/en-gb/revision-notes/gcse/science-practicals/national-curriculum/2-1-11-identifying-ions.md)
  - [2.1.12 Carbonates, Halides & Sulfates](https://senecalearning.com/en-gb/revision-notes/gcse/science-practicals/national-curriculum/2-1-12-carbonates-halides-and-sulfates.md)
  - [2.1.13 Flame Emission Spectroscopy](https://senecalearning.com/en-gb/revision-notes/gcse/science-practicals/national-curriculum/2-1-13-flame-emission-spectroscopy.md)
  - [2.1.14 Water Purification](https://senecalearning.com/en-gb/revision-notes/gcse/science-practicals/national-curriculum/2-1-14-water-purification.md)
  - [2.1.15 Water Purification 2](https://senecalearning.com/en-gb/revision-notes/gcse/science-practicals/national-curriculum/2-1-15-water-purification-2.md)

### 3 Physics
- 3.1 Practicals
  - [3.1.1 Specific Heat Capacity](https://senecalearning.com/en-gb/revision-notes/gcse/science-practicals/national-curriculum/3-1-1-specific-heat-capacity.md)
  - [3.1.2 Thermal Capacity & Insulation](https://senecalearning.com/en-gb/revision-notes/gcse/science-practicals/national-curriculum/3-1-2-thermal-capacity-and-insulation.md)
  - [3.1.3 Latent Heat](https://senecalearning.com/en-gb/revision-notes/gcse/science-practicals/national-curriculum/3-1-3-latent-heat.md)
  - [3.1.4 Resistance & Current](https://senecalearning.com/en-gb/revision-notes/gcse/science-practicals/national-curriculum/3-1-4-resistance-and-current.md)
  - [3.1.5 Resistance & Current 2](https://senecalearning.com/en-gb/revision-notes/gcse/science-practicals/national-curriculum/3-1-5-resistance-and-current-2.md)
  - [3.1.6 Density](https://senecalearning.com/en-gb/revision-notes/gcse/science-practicals/national-curriculum/3-1-6-density.md)
  - [3.1.7 Density 2](https://senecalearning.com/en-gb/revision-notes/gcse/science-practicals/national-curriculum/3-1-7-density-2.md)
  - [3.1.8 Force & Extension - Springs](https://senecalearning.com/en-gb/revision-notes/gcse/science-practicals/national-curriculum/3-1-8-force-and-extension-springs.md)
  - [3.1.9 Waves - Ripple Tank](https://senecalearning.com/en-gb/revision-notes/gcse/science-practicals/national-curriculum/3-1-9-waves-ripple-tank.md)
  - [3.1.10 Light](https://senecalearning.com/en-gb/revision-notes/gcse/science-practicals/national-curriculum/3-1-10-light.md)
  - [3.1.11 Light Reflection & Refraction](https://senecalearning.com/en-gb/revision-notes/gcse/science-practicals/national-curriculum/3-1-11-light-reflection-and-refraction.md)
  - [3.1.12 Radiation](https://senecalearning.com/en-gb/revision-notes/gcse/science-practicals/national-curriculum/3-1-12-radiation.md)
  - [3.1.13 Radiation 2](https://senecalearning.com/en-gb/revision-notes/gcse/science-practicals/national-curriculum/3-1-13-radiation-2.md)
