A wildlife survey uses an infrared camera to locate animals when there is no visible light. The same type of animal is observed at the same distance under two conditions.
| Condition | Detector reading from animal / mV | Detector reading from surroundings / mV |
|---|---|---|
| P | 78 | 65 |
| Q | 74 | 30 |
Give the reason why the infrared camera can locate an animal when there is no visible light.
Explain under which condition the camera is likely to locate the animal more reliably. Use data from the table in your answer.
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.