More microscopy- page 15

More Microscopy

Magnification is how many times bigger the image is

1. If you know the power of the lenses used by a microscope to view an image, you can work out the total magnification of the image using this simple formula:

Total magnification = eyepiece lens magnification x objective lens magnification

1. For example, the total magnification of an image viewed with an eyepiece lens magnification of x10 and an objective lens magnification of x40 would be 10 x 40 = x400.

2. If you don’t know which lenses were used, you can still work out the magnification of an image as long as you can measure the image and know the real size of the specimen. This is the formula you need:

Magnification = image size/real size     

Image size

Both measurements should have the same units. If they don’t, you’ll need to convert them first    (see below).

1. Real size

    

   X

    

   Magni-

   fication

    

   If you’re working out the image size or the real size of the object, you can rearrange the equation using the formula triangle. Cover up the thing you’re trying to find.                               The parts you can still see are the formula you need to use.

Estimating can help you to check that your answer is correct. To estimate an answer,                                                             round the numbers so you can do the maths in your head. E.g. say you know the real size of…