Resolution of a Microscope

A microscope not only magnifies the images but also separates minutes details. The ability of a Microscope to distinguish two very close objects as being separated from each other is its resolution or resolving power. Thus, if we look at two objects which are close together through a low resolution microscope, we see them ad a single object. However. Through a high resolution microscope we can distinguish the two objects. The resolving power is about half the wavelength of light (approximately 250 nm). Therefore , the resolving power of a light microscope is limited. At the most, it can distinguish two points which are 250 nm (0.25 um) apart and magnify about 1500 times. Since most cell organelles are smaller than 200 nm, they cannot be seen through a light microscope.

Note :  Microscopic objects are measured in microns. A micron is 1/1000 mm. The symbol for micron is the Greek letter u (mu). An even smaller unit is the nanometre (nm) which is 1/1000000 mm.