(©2007, François G. Amar, All rights reserved)

Summary for Week 9

Reading:

For this week: Chapter 6

A look ahead: End of chapter 6,

Homework problems:

Beginning of Chapter 6: 6.2, 6.5, 6.7, 6.15, 6.18, 6.23, 6.25, 6.28, 6.36

End of Chapter 6: 39, 41, 45, 47, 49, 51, 56, 59, 64, 72, 86

OWL Assignment for Week 9:

Chapter 6 assignment (called Ch 7 in OWL) quantum concepts: due November 11, 2007

Key concepts and equations:

Speed of light is constant (a fundamental constant of nature) :

c = 3.00x10⁸ m/s in vacuum

 

Wave nature of light (BLB section 6.1):

frequency, ("nu") units are #cycles per second = 1/s = s^-1 = Hertz (Hz)

wavelength, l ("lambda") units are meters = m (but may use nanometers, 1 nm=10^-9 m)

= c be able to convert from <-->

color of light is related to frequency, (ROY G BIV)

Discrete nature of light (BLB section 6.2):

h = 6.626x10^-34 J-s Planck's constant (a fundamental constant of nature)

E_photon = h energy of a photon whose frequency is (E_photon always positive)

Photoelectric effect

KE_electron = E_photon - W = h - W

where W is the work function (minimum energy needed to remove an electron from a metal)

Atoms have discrete energy levels, E₁<E₂<E₃ . . .

emission of light (from state 2 to state 1):

absorption of light (from state 1 to state 2) :

 

Line spectra of atoms (see Figures 6.11 and 6.12 of BLB)

Hydrogen atom and the Bohr model (BLB section 6.3)

R_H= 1.096776x10⁷ m^-1 = 109677.6 cm^-1 Rydberg constant

E_H =hcR_H= 2.18x10^-18 J "Rydberg constant" in energy units

 

 

Matter can act like a wave (BLB section 6.4)