ELECTROMAGNETIC ENERGY

Electromagnetic Energy

Travels through space as a combination of electric and magnetic field

Dual Nature

Behave as both wave and particle

Xrays, Gamma, UV

EM Examples

X-ray Properties

Highly penetrating

Invisible rays

Electrically neutral – Not affected by either electric or magnetic field

Polyenergetic and heterogenous

Travel at a speed of light in a vacuum

Travel in straight lines

Release a very small amount of heat upon passing through matter

Can ionize matter

Cause fluorescence of certain crystals

Cannot be focused by lens

Affect photographic film

Produce chemical and biological changes in matter

Produce secondary and scatterradiation

Wave Theory

EMR travels in a form of wave with an associated frequency and wavelength

Particle Theory

EMR acts like a small bundle of energy

Plankc’s Quantum Equation

E = hf

Equivalent Equation:

– f = E/h

– E = hc/λ

Planck’s Constant (h)

4.15 x 10-15 Ev-s

6.63 x 10-34 J-s

Frequency, Wavelength, Velocity, Amplitude

Properties of EM Energy

Frequency

The rate of rise and fall

Hertz

unit of frequency

1 Hz

1 cycle/second

Inverse

frequency relationship with wavelength

Wavelength

Usually measured from

– Crest to crest

– Valley to valley

– One point to other

Meter or Angstrom

unit of wavelength

Xray’s wavelength

10-10-10-14 m

0.1-0.5 Å

1018-1022 Hz

10 keV-50 MeV

Velocity

constant

speed of light

3 × 10^8 m/s, 186,400 mi/s

speed of light

Amplitude

The intensity of the wave defined by its maximal height

The width of a waveform

not related to wavelength or frequency

Photons

Smallest quantity of any EME

Small bundle of energy (quantum)

Travels at c

No mass and charge

Sinusoidal

photon waveform