# Microscopy

Most cells are too small to see with the naked eye. However, we can use microscopes to see the detail of very small objects, which can allow us to see what is happening inside cells.

In microscopy, ‘resolution‘ describes a microscope’s ability to distinguish detail. In other words, the shortest distance between two points that can still be distinguished as two separate entities. Different microscopes have different resolutions.

## Calculating the Magnification

Magnification is the ratio of two equivalent quantities; therefore, it does not have any units and is represented with an ‘x’ in front. E.g. x10 or x200

### Calculating the magnification of a microscope

A compound microscope is a microscope that uses two lenses to enhance the image of a sample. The two lenses are:

• The eyepiece lens (also known as the ocular lens)
• An objective lens

To work out the total magnification of the light microscope, the equation is:

So, if the eyepiece magnification is x10 and the objective lens magnification is x60, then the total magnification is:

10 × 60 = x600

### Calculating the magnification of an image

The magnification of an image can be calculated by using the equation:

If it’s easier, you can use the ‘equation triangle’ shown below to remember the formula.

So:

• Real size of image = Size of image / Magnification
• Magnification = Size of image / Real size of image
• Size of image = magnification × Real size of image

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