Calculating magnification DUMMY
Microscopes magnify an image by use of lens found in the eye-piece, which is also known as
theocular lens.The image is further magnified by theobjectivelens. Thus the magnification
of a microscope is:magnification power of the eye-piece x the power of the objective lens
Example:if the eyepiece magnification is 5X and the objective lens’ magnification is 10X,
the image of the object viewed under the microscope is 50X bigger than the object:
overall magnification=power of eyepiece×power of objective
= 5× 10
= 50×the original sizeCalculating the field of view
When viewing an object through a microscope, the diameter of the circle through which
you view the object is known as thefield of view.
As the magnification increases, the field of view decreases.
To measure the field of view, use a microscope slide with a tiny ruler printed on it. For
example, the size of the field of view shown below under low power magnification is ap-
proximately 1 mm.
Figure 3.6: Field of view is approximately 1 mmOnce the size of the field of view is known, we can estimate the size of the objects being
viewed under the microscope. At 10X magnification, the field of view is 1,0 mm. If the
magnification is increased to 100X, what will the new field of view be?
1,0 mm at 10 X magnification
new field of view=current magnification
new magnification
×current field of viewxmm at 100 X magnification
new field of view=current magnification
new magnification
×current field of viewx=10
100
×1,0 mm
=0,1 mmChapter 3. The basic units of life 67