Question

To investigate the structure of extremely small objects, such as viruses, the wavelength of the probing wave should be about one-tenth the size of the object for sharp images. But as the wavelength gets shorter, the energy of a photon of light gets greater and could damage or destroy the object being studied. One alternative is to use electron matter waves instead of light. Viruses vary considerably in size, but 50.0nm is not unusual. Suppose you want to study such a virus, using a wave of wavelength 5.15nm .

Part A

If you use light of this wavelength, what would be the energy (in eV) of a single photon?

Part B

If you use an electron of this wavelength, what would be its kinetic energy (in eV)?

Answer 1

Answer 2

Required Electron momentum, p = h/lambda = {6.62*(10^-34)}/{5.0*10^-9} = 1.324*10^-25 N m
KE = (p^2)/2m = [{1.324*(10^-25)}^2]/{2*9.1*(10^-31)} = 0.096*10^-19 J = (0.096/1.6) eV = 0.06 eV