Study Guide Part II - Modern Physics
Mrs. Ashley
College Physics
Name ____________________________________________
The following concepts will be covered on the test:
Static electricity
Unlike charges attract and like charges repel
Insulators and conductors
semiconductors
Coulomb's Law F = k Q1Q2
r2
K = 8.988 X 109 N m/C2
Permittivity of free space, K = 1/40
0 = 8.85 X 10 -12 C2/N m2
Electric charge is quantized
Remember that the electrostatic force between charged particles at rest is a vector
When working with the vectors of force between charged particles, sum components of the x and y axis
separately. Fx = F1cos an Fy = F1sin
You find the magnitude of the resultant force using Pythagorean formula
You find the direction by finding the angle  that F makes with the x axis by tan  = Fy
Fx
Remember to draw a picture in doing your problems
Electric Field
F = qE
E = F/q
E = kqQ/r2
q
For Uniform Electric Field
Field lines
Electric dipole
Electric potential
W = fd
Vba = -Ed
PEa - PEb =qEd
Electric potential is the electric potential energy per unit charge
V = PEa/ q
Potential difference is often called Voltage and is measured in Volts, only differences in potential energy
can be measured.
E = - Vba/d
Electron volts
Potential can be positive or negative
Potential due to electric dipole
V = kpcos (formula for dipole moment)
r2
Capacitance and capacitor
C = 0 A/d (finding the capacitance of a capacitor)
Finding the area of the capacitor is A = Cd
0
Electric Currents, chapter 18
Know the parts of a battery
What makes a battery produce a charge
Know parallel and series circuits
Know when a circuit is closed or open
Ohms law R = V/I
V = IR
Modern Physics You will not need to memorize all the formulas below, concepts and
understanding the example problems/how to solve is all that is needed.
Relativity principle
Reference frames
Inertial reference frame
Simultaneity
Time dilation
Length contraction
proper length
relativistic momentum and mass
rest mass
E = mC2
KE = moC2
1-v2/c2
Wien's Law T = 2.90 X 10-3 m K
E = hf
h is Planks Constant; f is the frequency and E is the energy
hf = KEmax + W0 Use this formula when electrons are ejected from a substance.
f = c/
hf = hc/
Photon momentum is found: p = h/
Know the photon interactions and pair production
 = hc/E
Know the wave particle duality
Understand principle of complementarity
de Broglie wave nature of mater  = h/p
Rutherford's model of the atom
Bohr model of the atom n2 r
Z
Atomic spectra
Energy levels, ground state and excited states
Quantum mechanics of atoms
The relationship between wave and particle
Heisenberg Uncertainty principle
Δx =ħ/Δp