(©2002, François G. Amar, All rights reserved)

Summary for Week 8

Reading:

For this week: Chapter 6

A look ahead: End of chapter 6,

Homework problems:

Beginning of Chapter 6: 6.3, 6.4, 6.7, 6.13, 6.18, 6.22, 6.25, 6.29, 6.35

End of Chapter 6: 39, 41, 45, 47, 49, 51, 56, 59, 65, 69

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, n ("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)

n l = c be able to convert from n <--> l

color of light is related to frequency, n (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 = hn energy of a photon whose frequency is n (E_photon always positive)

Photoelectric effect

KE_electron = E_photon - F = hn - F

where F 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 6.14 and 6.15 of BLB)

Hydrogen atom and the Bohr model (BLB section 6.3)

R_H = 2.18x10^-18 J Rydberg constant

 

 

Matter can act like a wave (BLB section 6.4)