1. Radiant Energy Objectives:
1. Describe a wave in terms of its frequency, speed, and amplitude.
2. Identify the major regions of the electromagnetic spectrum.
Key Terms:
electromagnetic radiation, amplitude, wavelength, frequency, speed of light, visible spectrum

2. Waves and Energy
A wave is a disturbance that transfers energy through a medium.
All waves can be characterized by the following four characteristics: amplitude, wavelength, frequency, and speed.
Light travels in electromagnetic waves.
The Photon has a dual nature. (double transverse wave)
One part light and mass.
Or …one part electric and one part magnetic
This dual nature allows the photon to travel through space.

3. Amplitude
The maximum distance the molecules are displaced from the midline
Or... The distance from the midline to the crest or trough
As energy , amplitude 
crest
midline
trough

4. Wavelength The distance between 2 consecutive crests or troughs
Unit is the meter or nanometer (1nm = 1x10-9m)

5. Frequency
The number of crests of troughs passing a point per unit time
Transverse … crests(troughs)/second
Symbol is v & unit is the hertz (Hz) 1Hz = 1/s or s-1

6. Speed of Waves Speed in any given medium is constant.
Speed (c) = frequency (v or f)  wavelength () or c = v x 
If Hz  then  or if Hz then  
A medium is any substance or region through which a wave is transmitted.
Transfers energy only without any net movement of the medium

7. Light Energy The atom is the source of all light.
When an atom absorbs a quantum of energy its electrons (e-) become excited and jump to higher energy orbits (excited state)
As the excited e- looses energy, it falls back to its original orbit (ground state) and releases a photon.
A photon is a tiny packet or bundle of energy that contains the exact amount of energy that the atom absorbed
The amount of energy a photon contains
determines what type of light is emitted
Light Energy

8. Electromagnetic Spectrum
The frequencies of light created as an atom reaches quantum requirement is called a line spectrum.
a line spectrum (or emission spectrum)contains only certain frequencies of light which can be seen by passing the emitted light through a prism

9. Plank’s Equation
Plank's theory states that each element can only absorb a certain amount of energy (quantum) therefore it can only emit a limited amount of energy. Each element absorbs energy only when the quantum is reached. This was further explained by the equation:
Plank used this concept to describe why certain elements give of different color lights emit different colors.
E = hv
if you know the amount of energy absorbed you can calculate the wavelength using the formula for wave speed (c = v x )
Frequency Hz or /s
Plank’s Constant
x 10-34
Quantum energy requirement