And Its

What is Electromagnetic Spectrum? The electromagnetic spectrum is a

collection of electromagnetic waves arranged according to frequency and wavelength.

How EMR’s are formed

Electromagnetic waves are formed when an electric field (which is shown in blue arrows) couples with a magnetic field (which is shown in red arrows).

WHAT ARE WAVES? WHAT IS WAVELENGTH?

WAVELENGTH:

It is the distance from one point on a wave to the corresponding point on the next consecutive wave.

WAVES:

Waves are a series of crests and troughs moving past a given reference point.

WHAT ARE ELECTROMAGNETIC WAVES?

Static electricity can make your hair stand on end. Magnets can attract certain metals.

Radio waves, TV waves and microwaves are all types of electromagnetic waves. However, they differ in wavelength and energy.

POWER DECIMAL PREFIX PHONIC SYMBOL OF TEN EQUIVALENT10 12 1 000 000 000 000 tera ter'a

T

10 9 1 000 000 000 giga gi'ga G

10 6 1 000 000 mega meg'a M

10 3 1 000 kilo kil'o k

Scientific Notation

FREQUENCY = the number of cycles per second

HERTZ = the unit attached to frequency

COMPARISON OF WAVE LENGTHS WITH IN THE ELECTROMAGNETIC SPECTRUM

EMR SPECTRUM EMR SPECTRUM CHARACTERISTICS CHARACTERISTICS

----

---

Energy

Wavelength

Frequency

Radio Micro Infra Visible UV X-rays Gamma

Waves Waves Red Light Light Rays

Common Hertz Relationships

HERTZ TYPE____________________________________________________________________________________________________

approximately 60 Electrical power_______________________________________________________________________________

5 - 20000 (20 k) audio frequencies - human _______________________________________________________________________________

10 k - 30 G radio frequencies _______________________________________________________________________________

540 k -1600 k Amplitude Modulation (AM)_______________________________________________________________________________

88 M -108 M Frequency Modulation (FM)________________________________________________________________________________

30 M - 300 M VHF - TV (very high frequency) ________________________________________________________________________________

54 M - 890 M CATV (Cable Antenna Television) ________________________________________________________________________________

300 M - 3000 M (3 G) UHF - TV (ultra high frequency) ________________________________________________________________________________

3 G - 30 microwave (super high frequency) ________________________________________________________________________________

FEDERAL

COMMUNICATIONS

COMMISSION

Government Agency that Monitors and Controls Mass Communication Industries

WHY USE MICROWAVES

FOR COMMUNICATION?

Microwaves are good for transmitting information because their energy can penetrate fog, light rain and snow, clouds and smoke.

SATELLITE ORBITS

Three basic kinds of orbits:

1) GEOSYNCHRONOUS

- also called Geostationary or Synchronous)

2) Asynchronous

- used by space shuttle

- very low altitude (400 miles)

- pass over at different times of the day

3) Polar

- low altitude

- passes over the earth’s poles on each revolution

References

Date obtained: September 21, 2005

http://imagers.gsfc.nasa.gov/ems/ems.html Date obtained: September 21, 2005

http://imagine.gsfc.nasa.gov/docs/science/know_l1/emspectrum.html