Question

We wish to see inside an atom. Assuming the atom to have a diameter of 100 pm, this means that one must be able to resolve a width of say 10 pm. If an electron microscope is used, the minimum electron energy required is about

(a) 1.5 keV

(b) 15 keV

(c) 150 keV

(d) 1.5 MeV

Answer 1

The correct option is (b) 15 keV.

Explanation:

In electron microscope, electrons are used as the light source. The resolving power of a microscope is approximately equal to that of wavelength of the light used. The de Broglie wavelength λ of a particle is related to its momentum p by