electromagnetic spectrum deals with range of frequency arranged in amanered order of theier respective wave leghes of diferent ranges.

1. Electromagnetic
Radiation

2. Waves… a review
Most waves are either
longitudinal or transverse.
Sound waves are longitudinal.
But all electromagnetic waves
are transverse…

3. ?
?

4.  Electromagnetic Spectrum—name for
the range of electromagnetic waves
when placed in order of increasing
frequency
RADIO
WAVES
MICROWAVES
INFRARED
RAYS
VISIBLE LIGHT
ULTRAVIOLET
RAYS
X-RAYS
GAMMA
RAYS

5. Electromagnetic waves
 Produced by the movement of
electrically charged particles
 Can travel in a “vacuum” (they do
NOT need a medium)
 Travel at the speed of
light c= 3.0 x 108 m/s
 Also known as EM waves

6. What is the relationship between frequency and
wavelength?
INVERSE
(as one goes up, other goes down)

7. Radio waves
 Longest wavelength, lowest energy
 Uses:
 TV broadcasting
 AM and FM broadcast radio
 Heart rate monitors
 Cell phone communication
 MRI (MAGNETIC RESONACE IMAGING)
 Uses Short wave radio waves with a magnet to create an image

8. Microwaves
 Wavelengths from 1 mm- 1 m
 Uses:
 Microwave ovens
 Bluetooth headsets
 Broadband Wireless Internet
 Radar
 GPS

9. Infrared Radiation
 Wavelengths in between microwaves
and visible light
 Uses:
 Night vision goggles
 Remote controls
 Heat-seeking missiles

10. Visible light
 Only type of EM wave able to
be detected by the human eye
 Violet is the highest frequency
and energy light
 Red light is the lowest
frequency light and lowest
energy

11. Ultraviolet
 Shorter wavelengths than visible light
 Uses:
 Black lights
 Security images on money
 Harmful to living things
 Used to sterilize medical equipment
 Too much causes sun burn
 Extremely high exposure can cause skin cancer

12. X-rays
 Tiny wavelength, high
energy waves
 Uses:
 Medical imaging
 Airport security
 Moderate dose can damaging to cells

13. Gamma Rays
 Smallest wavelengths, highest energy EM
waves
 Uses
 Sterilizes medical equipment
 Cancer treatment to kill cancer cells
 Kills nearly all living cells.

14. Waves or Particles
• Electromagnetic radiation has
properties of waves but also can be
thought of as a stream of
particles.
 Example: Light
 Light as a wave: Light behaves as a transverse wave
which we can filter using polarized lenses.
 Light as particles (photons): When directed at a
substance light can knock electrons off of a substance
(Photoelectric effect)

15. Emission of Light
 Quantum – minimum amount of
energy that can be gained or lost by
an atom; can be referred to as a
packet of energy
 Photon – packet of light energy
(quantum)

16. ) ) ) ) ) )
)
1 2 3 4 5 6 7
Electrons & Light
 As energy is absorbed,
the electrons move
from their ground
state (original energy
level) to an excited
state (higher energy
level)
energy levels
ground state excited state
Initial position Final position
nucleus
Light & Energy
5.1

17. ) ) ) ) ) )
)
1 2 3 4 5 6 7
nucleus
energy levels Initial position
Final position
excited state
ground state
Light & Energy
5.1
Electrons & Light
 Electrons are unstable in
their excited state, so
they return to the ground
state by releasing
energy. During this
return, light is emitted!

18. Spectra of Light
 Emission Spectra - A set of frequencies of the
electromagnetic waves emitted by atoms of the
element
 Shows all the wavelengths of light that are emitted
 Spectroscope – instrument used to see the emission
spectra
 Unique to each element
Light & Energy
5.1