Question

When will you use a simple microscope and when, a compound microsope? Explain in detail how you will use them.

Answer 1

A simple microscope is only equipped with one biconvex lens, often with a short focal length. A simple microscope is used to produce an enlarged image of an object placed within its focal length. On the other hand, a compound microscope has two sets of lenses, an ocular or eyepiece lens and the objective lenses. A simple microscope has only one level of magnification, i.e. its magnification is not adjustable and is equivalent to the lens used. The compound microscope has a much higher level of magnification and is adjustable.

A simple microscope is used at a basic level, where there is no rigorous requirement of research. There are 3 to 5 objective lenses in a compound which helps in magnifying algae, fungi and bacterium. Its total magnification is limited to the magnification of the single lens used.

A compound microscope is used to see cells and subcellular parts in details. It is also used to compare differences among various cells and abnormalities in them for e.g. because of diseases.

A simple microscope works on the principle that when a tiny object is placed within its focus, a virtual, erect and magnified image of the object is formed at the least distance of distinct vision from the eye held close to the lens. So, for seeing a magnified version of an object by simple microscope we need to put it within focal length of lens.

The compound microscope contains a number of optical parts, which allow for the magnification and visualization of slides. The eyepiece is what we look through to see slide. This eyepiece usually has a magnifying power of 10X, but some eyepieces have magnifying powers of 5X to 30X.

Objective lenses range from 4X to 100X and are the primary optical lenses on this piece of equipment. The eyepiece tube holds the eyepieces in place. The nosepiece contains the objective lenses, which are mounted on a rotating part. This allows us to select different objectives.

Focus knobs allow us to focus the microscope properly. When using a microscope, we place the specimen on a stage. Some microscopes have a mechanical stage, which allows for very minute slide movements. If the microscope does not have a mechanical stage, it also has stage clips that allow the user to move a slide manually. The illuminator contains the lighting for the microscope.

The iris diaphragm regulates the amount of light that reaches a slide. This part works with the condenser, which collects the light from the illuminator. Both parts help to control the focus and amount of light applied to the slide.