Electromagnetic waves are used in many different applications because of their different properties. Describe the properties and uses of infrared radiation, microwaves, and radio waves, and explain why each type is suited to its application.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Model answer (5 marks)
Infrared radiation is emitted and absorbed by all objects; it is used for cooking, thermal imaging and short‑range communications. It can cause skin burns, so the hazard is correctly identified.
Microwaves are used for satellite communications and for cooking food. They can cause internal heating of body cells, so the hazard is correctly identified.
Radio waves are used for television and radio signals. They can be produced by oscillations in electrical circuits or can induce these oscillations themselves.
Microwaves are used for satellite communications and for cooking food. They can cause internal heating of body cells, so the hazard is correctly identified.
Radio waves are used for television and radio signals. They can be produced by oscillations in electrical circuits or can induce these oscillations themselves.
Examiner tips
- Use the exact terminology from the mark scheme (e.g. ‘emitted and absorbed by all objects’).
- Show the hazard for each type to gain the full marks for the ‘hazard correctly identified’ point.
- Keep the answer concise – one sentence per type – to fit the 5‑mark limit.
Common mistakes
- Writing the properties in a list rather than a paragraph, losing the ‘describe’ command word.
- Omitting the hazard for any wave type, losing 1 mark.
Mark scheme (5 marks)
- Infrared radiation is emitted and absorbed by all objects / used for cooking, thermal imaging, or short-range communications
- Infrared can cause skin burns (hazard correctly identified)
- Microwaves are used for satellite communications and/or cooking food
- Microwaves can cause internal heating of body cells (hazard correctly identified)
- Radio waves are used for television and/or radio signals, and can be produced by oscillations in electrical circuits or can induce these oscillations themselves
Key terms in this question
infrared radiation · microwaves · radio waves · electromagnetic waves
Related
- All WJEC A-Level Physics (Wales) revision notes →
- How to answer a "Describe" question →
- Decode the mark scheme abbreviations →
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