Lenses are precisely shaped pieces of glass that have been developed and used in corrective glasses, telescopes, microscopes, binoculars, and magnifying glasses.
magnification The ratio of the image height to the object height when using lenses. is a measure of the size of an image compared to the size of the object. Lenses and curved mirrors can produce magnified images.
Calculating magnification
The magnification produced by a lens can be calculated using the equation:
Magnification is a ratio of two lengths, so it has no units. However, the image height and object height should both be measured in the same units, eg centimetres (cm) or millimetres (mm), but not a mixture of the two.
Example 1
An object that is 2 cm tall forms an image 250 cm tall. Calculate the magnification.