A student investigates how the surface of a can affects the infrared radiation the can emits. The student uses four cans with different surfaces. Which variable must the student control?
The colour of the surface of each can
The texture of the surface of each can
The type of scale marked on the thermometer
The starting temperature of the water in each can
40 exam-style questions on AQA GCSE Physics 6.2 Electromagnetic waves, covering 6.2.1 Types of electromagnetic waves, 6.2.2 Properties of electromagnetic waves 1, 6.2.3 Properties of electromagnetic waves 2, 6.2.4 Uses and applications of electromagnetic waves, 6.2.5 Lenses, and 6.2.6 Visible light. Each one has a worked solution and a mark scheme showing where the marks go.