Ultraviolet radiation has several uses.
A shop worker uses an ultraviolet lamp to check bank notes.
Describe how the ultraviolet lamp shows whether a bank note is genuine or forged.
The lamp is fixed so that the ultraviolet radiation shines down onto the bank note and not towards the worker's face.
Explain why.
Ultraviolet radiation is also used to disinfect drinking water.
Explain how ultraviolet radiation makes the water safe to drink.
In a water treatment unit, water flows along a straight tube past an ultraviolet lamp.
The length of tube lit by the lamp is 1.2 m.
The water flows along the tube at an average speed of 0.15 m/s.
To be disinfected, the water must be exposed to the ultraviolet radiation for at least 10 s.
Determine whether the water is disinfected.
Use the equation
average speed=distance÷time\text{average speed} = \text{distance} \div \text{time}average speed=distance÷time
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.