Electromagnetism Flashcards
Photon
smallest quantity of any time of EM radiation, atom of light
Properties of photons
Move at speed of light; travel in a sine wave
Properties of EM radiation
frequency, velocity, amplitude, wavelength
Frequency
Waves per second (Hz); =velocity/wavelength
Velocity
distance in time (m/s); =frequency*wavelength
Amplitude
intensity of the wave
Wavelength
A=velocity/frequency
Electromagnetic Wave equation
C = frequency*wavelength (frequency and wavelength are inversely proportional)
Inverse Square Law
I1/I2 = (d2/d1)^2
Wave-Particle Duality
Electromagnetic radiation has properties of both a wave and a particle (travel through space as a wave and have ability to ionize)
Electromagnetic Spectrum
Gamma Rays (highest energy, highest frequency, shortest wavelength), UV light, Visible light, Infared, microwaves, radiofrequency (lowest energy, lowest frequency, longest wavelength)
Radiopaque
absorb x-rays; bone (absorption-high atomic number)
Radiolucent
transmit x-rays; soft tissue (transmission-low atomic number)
Attenuation
light is transmitted but scattered (translucent)
Particle Model: Quantum Theory
x-rays are identified by their energy in eV (typically 10 keV - 50 MeV
Planck’s Constant
photon energy is directly proportional to photon frequency
E=hf (h=4.15X10^-15 eVs)
Planck’s Quantum Equation
F=E/h
E=hc/wavelength
Electrostatics
branch of physics that deals with stationary or resting charges
Electrification
process by which electrons are added or ejected from matter, making the atom charged (too few or too many electrons)
Electrons
smallest unit of electron charge
methods of electrification
friction, contact, induction
Induction
electrical fields interact without touching
Conductors
copper, aluminum
Insulators
plastic, rubber, glass, wood
Semi-conductors
silicon, germanium
Law #1 electrostatic force
like charges repel, unlike charges attract
Law #2 Coulomb’s Law
electrostatic force is directly proportional to the product of the electrostatic charges and inversely proportional to the square of the distance between them
Law #3 Distribution
Electric charge distribution is uniform throughout the surface
Law #4 Concentration
concentration of charges on a curved surface is greatest where the curvature s greatest
Law #5 Movement
only negative charges can move in solid conductors