A radio aerial is mounted inside a protective housing. The housing must let radio signals reach the aerial but reduce the gamma radiation from a nearby source that reaches it.
An engineer directs a radio-wave pulse and a gamma-ray pulse at a sample of the housing material. Each pulse has an incident energy of 100 μJ100\ \mu\mathrm{J}100 μJ.
| radiation | frequency in Hz | energy transmitted in μJ\mu\mathrm{J}μJ | energy reflected in μJ\mu\mathrm{J}μJ |
|---|---|---|---|
| radio waves | 1.0 × 108 | 74 | 16 |
| gamma rays | 3.0 × 1020 | 13 | 2 |
Electromagnetic waves travel at 3.0×108 m s−13.0\times10^8\ \mathrm{m\,s^{-1}}3.0×108 ms−1 in a vacuum.
Evaluate whether the material is suitable for the housing. Use calculations based on the data and your knowledge of electromagnetic waves in your answer.
84 exam-style questions on Edexcel GCSE Physics 5.2 The electromagnetic spectrum, covering 5.2.1 Electromagnetic waves and refraction in glass (core practical), 5.2.2 Groups of the electromagnetic spectrum, 5.2.3 Wavelength-dependent behaviour of EM waves, and 5.2.4 Velocities of EM waves in different substances. Each one has a worked solution and a mark scheme showing where the marks go.