Name: Optical Instruments: Spectrometer
Uploaded: 2019-07-19
Duration: 7 min 33 s
Description: The basic function of a spectrometer is to take in light, break it into its spectral components, digitise the signal as a function of wavelength, and read it...

Question

Describe a compound microscope. Explain, with the help of a neat diagram, how it produces a magnified image.

Accepted Answer

A compound microscope is defined as:

A microscope with a high resolution and uses two sets of lenses providing a 2-dimensional image of the sample.

The term compound refers to the usage of more than one lens in the microscope. Also, the compound microscope is one of the types of optical microscopes.

A compound microscope is considered to be one of the standard microscopes that can be used for general purposes. The arrangement of the lens is such that it magnifies the objects from the complex system.

There are two types of lenses that are used in the compound microscope:

The objective lens is placed close to the object that needs to be examined.

The eyepiece allows the image to be viewed. The eyepiece is also known as the ocular lens.

The light is made to pass through the thin transparent object. A magnified image of the object is obtained by the objective lens. This image is known as the real image. The eyepiece or the ocular lens then magnifies the real image more and is viewed as the virtual image. The compound microscope is also known as the bright-field microscope because the light passes directly through the light source to the eye through the two lenses. This mechanism makes the field of vision brightly illuminated.

The ray diagram to show the working of compound microscope is shown in figure. A tiny object AB to be magnified is placed in front of the objective lens just beyond its principal focus $f_{o}$ . In this case, the objective lens O of the compound microscope forms a real, inverted and enlarged image A’ B’ of the object. Now A’ B’ acts as an object for the eye piece E, whose position is adjusted so that A’ B’ lies between optical centre and the focus $f_{e}$ of eye piece. Now the eye piece forms a final virtual, inverted and highly magnified image A” B”. this final image A”B” is seen by our eye hold close to eye piece, after adjusting the final image A” B” at the least distance of distinct vision of 25 cm from the eye.

Describe a compound microscope. Explain, with the help of a neat diagram, how it produces a magnified image.

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