A sports centre uses an infrared heater and a microwave transmitter for a satellite communication link.
The speed of electromagnetic waves is 3.0 × 108 m/s.
The microwave transmitter produces a signal with a frequency of 5.0 × 109 Hz.
The wavelength, λ\lambdaλ, of the signal is given by
λ=vf\displaystyle \lambda = \frac{v}{f}λ=fv
Calculate the wavelength of the microwave signal.
High-intensity radiation from either source can affect body tissue.
State whether each effect is caused mainly by infrared radiation or by microwaves.
| Effect | Type of radiation |
|---|---|
| P: energy is absorbed mainly near the skin surface and may cause burns | |
| Q: radiation penetrates into body tissue and may cause internal heating |
State one precaution that a maintenance worker can take to reduce exposure to either source.
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.