Light and Reflection
Light travels in straight lines and reflects from surfaces, forming images in mirrors.
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Light travels in straight lines and reflects from surfaces, forming images in mirrors.
- Plane mirror images are the same size
- The image is virtual and laterally inverted
- Light speed is about 300,000 km per second
🧠 Quick quiz
Three questions. Score 2 or more to complete the topic.
What is Light and Reflection?
Within Physics, which covers forces, energy, waves, electricity, magnetism, light and space explained through motion and experiments, this topic explains Light and Reflection. Physics topics explain how things move, push, heat up and carry energy, so each one here pairs a definition with a live model you can change.
Check that you can explain Light and Reflection in your own words and give one example from everyday life. If you can do that, you have understood the core idea.
Understanding Light and Reflection explains how the physical world behaves, from sport and transport to electricity and medicine.
Light and Reflection in detail
Light is a transverse electromagnetic wave that travels in straight lines at about 3 × 10⁸ m/s in a vacuum. We see objects because they emit or reflect light into our eyes. Shadows form because light cannot bend around opaque objects.
The law of reflection, angle of incidence equals angle of reflection, applies to mirrors. A plane mirror produces a virtual, upright, laterally inverted image the same size as the object and as far behind the mirror as the object is in front. Ray diagrams use the normal to measure angles and are used in periscopes and reflectors.
How the interactive helps you understand Light and Reflection
Watch the light rays in the interactive. Use any sliders or buttons it offers to change the values and see how the light rays responds.
Before you change anything, predict the result. Then change one value at a time and check whether your prediction was right. This is a quick way to build a correct mental model of Light and Reflection.
Real-life uses and examples
- Predict what a ball, car or circuit will do with Light and Reflection before you do the calculation.
- Explain everyday devices, such as brakes, lifts or chargers, using Light and Reflection.
- Use Light and Reflection to make sense of a practical and its results.
Common mistakes to avoid
- Mixing up Light and Reflection with a related quantity that has different units.
- Forgetting that some quantities, such as force or velocity, also have a direction.
- Learning the definition without testing it. Use the quiz and the interactive to check that you can apply the idea.
Frequently asked questions about Light and Reflection
What is Light and Reflection?
Light travels in straight lines and reflects from surfaces, forming images in mirrors.
What are the most important points about Light and Reflection?
The main points are: Plane mirror images are the same size; The image is virtual and laterally inverted; Light speed is about 300,000 km per second.
Why is Light and Reflection useful?
Understanding Light and Reflection explains how the physical world behaves, from sport and transport to electricity and medicine.
How can I practise Light and Reflection?
Open the interactive at the top of this page and change the controls one at a time. Predict the result before each change, then take the three-question quiz. A score of two or more marks the topic as complete on this device.
Which topics are related to Light and Reflection?
Related topics in Physics include Lenses, Electromagnetic Spectrum, Electric Current.