What is the term used to describe the distance from the centre of a lens to its principal focus?
An image formed by a lens can be either real or virtual. State one difference between a real image and a virtual image.
A scientist uses a lens to examine a tiny specimen.
Calculate the actual height of the specimen. Use the equation: magnification=image heightobject height\text{magnification} = \frac{\text{image height}}{\text{object height}}magnification=object heightimage height