The speed of electromagnetic waves is 3.0 × 108 m/s.
The label on a workshop heater gives these values for the infrared radiation it emits.
| Quantity | Value on label |
|---|---|
| frequency | 1.2 × 1013 Hz |
| wavelength | 2.0 × 10-5 m |
Use a calculation to evaluate whether both values on the label can be correct.
A worker in the workshop could be exposed to infrared radiation and microwaves under the following conditions.
| Radiation | Exposure condition |
|---|---|
| Infrared | high intensity for 2 minutes |
| Microwaves | low intensity for 20 minutes |
A safety officer says:
'Infrared must be more harmful because it has a higher frequency than microwaves.'
Discuss the safety officer's statement.
104 exam-style questions on Edexcel GCSE Physics 5.4 Uses and dangers of EM radiation, covering 5.4.1 Dangers of electromagnetic radiation, 5.4.2 Uses of electromagnetic radiation, 5.4.3 Radio waves and oscillations in circuits, and 5.4.4 Changes in atoms and nuclei generating radiation. Each one has a worked solution and a mark scheme showing where the marks go.