Question

Which of the following is not a part of an Electron Microscope?

(a) Electron Gun

(b) Objective

(c) Magnetic lens

(d) Fluorescent Screen

This question was posed to me during a job interview.

I want to ask this question from Optical Instruments in section Optics of Engineering Physics II

Answer 1

Right choice is (b) Objective

For explanation I would say: The electron microscope works on the principle that a beam of electrons exhibit wave nature and they can be focused by suitable electric and magnetic fields. Thus, electron microscope has an electron gun for producing electrons, a Magnetic lens to focus the electron beam and the fluorescent screen to obtain the image.