Year 11 - Science
Refraction through a semicircular block (including TIR)
Electromagnetic waves
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This pupil-friendly study guide includes a unit summary, clear notes, common mistakes, and quick questions with answers.
Unit Summary
This unit explores reflection, refraction, and lenses using ray diagrams. It covers the electromagnetic spectrum, light as a wave, absorption, transmission, and practical uses. Emphasis is on risks, temperature balance, data presentation, and unit conversions.
Lesson Summary
You will learn to describe and explain when refraction happens and when total internal reflection happens at boundaries between media.
Key Notes
- At a boundary to a medium where the wave speed increases, waves are refracted away from the normal.
- If the angle of incidence is too big (bigger than the critical angle) the waves will undergo total internal reflection.
- The critical angle is the greatest angle of incidence before total internal reflection occurs.
- For a glass–air boundary, the critical angle (c) is about 42°.
Vocabulary To Learn
- refraction: Refraction occurs when waves travel from one transparent medium to another, causing a change in direction.
- medium: A medium is the material through which a wave is travelling.
- angle of incidence: The angle of incidence is the angle between the incident ray and the normal.
- total internal reflection: Total internal reflection is when waves fully reflect from a boundary to a medium when greater wave speed, rather than being transmitted through.
- critical angle: The critical angle is the greatest angle of incidence before total internal reflection occurs for a boundary to a medium with greater wave speed.
Common Mistakes To Avoid
- Pupils sometimes rote-learn what specific examples of refraction look like, rather than developing a more general understanding of the direction waves turn based on changes in wave speed.
3 Quick Questions (With Answers)
1. Explain the scientific idea in this lesson using two key points.
At a boundary to a medium where the wave speed increases, waves are refracted away from the normal. If the angle of incidence is too big (bigger than the critical angle) the waves will undergo total internal reflection.
2. Define this scientific word and use it in context. 'refraction'
Refraction occurs when waves travel from one transparent medium to another, causing a change in direction. Include the word in a full scientific explanation, not as a single label.
3. Correct this common scientific misunderstanding.
Mistake: Pupils sometimes rote-learn what specific examples of refraction look like, rather than developing a more general understanding of the direction waves turn based on changes in wave speed. Correction: Teach pupils the general theory of refraction and apply it to a variety of different examples where wave speed changes (e.g. sound waves refract in the opposite direction to light at an air-glass boundary due to the different wave speeds).
More Lessons In This Unit
- Absorbing infrared radiation practical Study Guide
- Converging lenses Study Guide
- Convex lenses Study Guide
- Convex lenses (including magnification) Study Guide
- Dispersion of light and electromagnetic radiation Study Guide
- Dispersion of light and electromagnetic waves Study Guide
- Emitters of infrared & black body radiation Study Guide
- Emitting infrared and black body radiation Study Guide
- Emitting infrared radiation Study Guide
- Ionising electromagnetic radiation Study Guide
- Light and colour Study Guide
- Non-ionising electromagnetic radiation Study Guide
- Non-ionising electromagnetic radiations Study Guide
- Reflection of light Study Guide
- Reflection of light (including specular and diffuse) Study Guide
- Refraction through a rectangular block Study Guide
- Refraction through a rectangular block (including wave front diagrams) Study Guide
- Refraction through a semicircular block Study Guide
- Scale diagrams for converging lenses Study Guide
- Scale diagrams for convex lenses Study Guide
- Scale diagrams for convex lenses (including magnification) Study Guide
- The spectrum of electromagnetic radiation Study Guide
- The spectrum of electromagnetic waves Study Guide
- Virtual images from converging and diverging lenses Study Guide
- Virtual images from convex and concave lenses Study Guide
- Virtual images from convex and concave lenses (including magnification) Study Guide
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