An autonomous unit uses ultraviolet radiation to disinfect the floor of an empty sports hall.
The unit travels at a constant speed. Its lamp illuminates a 0.90 m length of floor in the direction of travel, so each point on the floor is illuminated while the unit travels this distance.
Each point must be illuminated for at least 15 s to be disinfected.
The unit must complete a 24 m route in no more than 6.0 minutes6.0\ \text{minutes}6.0 minutes.
Use the equation
average speed=distance÷time\text{average speed} = \text{distance} \div \text{time}average speed=distance÷time
Determine whether there is a constant speed at which the unit can meet both requirements.
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.