Question

The PI of the lab you are working in this summer wants to study the structure E. coli, which are about 2 µm long. To observe the E. coli, you will want to use either photons or electrons that have a wavelength comparable to the size of the E. coli. The PI asks you if it would be better to use a traditional light microscope or an electron microscope. How do you respond? (Hint: the bacteria are more likely to be damaged by higher energy particles).

note: I would like a physics explanation to this question that has to do with the indicated "2 µm" length of the E. coli structure and to explain the effect of photons and electrons.

Answer 1

In order to observe an object of 2um long the wave length of electron must be atleast 2 um.

according to de broglie wavelength of a electon is given by

minimum momentum of the electron is

energy of the electron is

energy of a photon with 2um wavelength is

the Energy of photon with 2um wave length is much higher than the energy of electron of same wavelength.

Therefor an electron Microscore is suggested.