PHYS 1010Q Lecture Notes - Lecture 32: Scanning Tunneling Microscope, Atomic-Force Microscopy, Scanning Electron Microscope

• School: UConn
• Department: Physics
• Course: PHYS 1010Q
• Professor: Douglas Hamilton

Document Summary

Niels bohr developed the model of an atmo to bring some order to the confusion of the model of atoms at the time. E = e 2 - e 1 = -3. 4 ev - (-13. 6 ev) Question 1 - an electron in a h atom relaxes from the n=3 level to the n=2 level. Energy of the photon = +1. 9 ev. Using the chart given, you can see that this photon energy falls into the red section. The limit of an optical microscope is how well the light can focus. Light (a wave) can be focused to about . So, mid-vision is 550 nm, b=est resolution is about 275 nm. Electrons also behave like waves, but have much smaller wavelength. A 200 kev electron has a wavelength of 2. 5 pm - 0. 0025 nm. But now electron beam goes through sample (must be thin) Direct absorption tell us electron density in path (i. e. atoms or not)