State the term used for the distance between the principal focus and the optical centre of a lens.
Explain one difference between a real image and a virtual image formed by a lens.
An engineer uses a magnifying lens to inspect a trace on a circuit board.
Calculate the actual height of the trace. Use the equation:
magnification=image heightobject height \text{magnification} = \frac{\text{image height}}{\text{object height}} magnification=object heightimage height29 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.