Question

What type of objective lens will have the least working distance?

• A. 5X
• B. 10X
• C. 45X
• D. 100X

Answer 1

Answer: (D)

100X

In a microscope the optical element which lies closest to the specimen is the objective lens. It gather light from the specimen which produces a real image i.e seen via an ocular lens or eyepiece. Objective lenses have a multi element design which makes them the most important and most complex part of microscope. Objective lenses are responsible for the primary image its total magnitude and the quality and resolution of the image. Based on the magnification power the objective lens is of the following types:-

Low magnification objective lens(5X and 10X)

Intermediate magnification objective lens (20X nd 40X)

High magnification objective lens (100X)

Working distance is the distance between the specimen and the first lens where light waves are reflected. So, the high magnification objective lens has to be closer to the specimen to focus the object and the low magnification objective lens requires more distance to focus the object. So, the working distance will decrease with an increase in magnification the least will be the working distance. so, the objective lens with 100X magnification will have the least working distance and an objective lens with magnification 5X will have and an objective lens with magnification 5X will have maximum distance.

So, the correct answer is (D)