Question

what is meant by internal vaccum of a microscope? why internal vaccum is essential for the working of electron microscope and not light microscope? can light microscope work in internal vaccum?

Answer 1

A light microscope uses light as its illumination source where as an electron microscope uses electrons. Vacuum is needed for the electrons to travel from the electron source to the sample surface unimpeded.

Without vacuum the beam of electrons would be scattered (mean free path is low) by air particles. So, a high level of vacuum is needed for an electron microscope( mean free path of the electron should be larger than the electron column).

Answer 2

Answer:

Something very small. Kritam was probably the tiniest of the seven thousand villages in India as it was a microscopic dot on the survey map.