How to read this chart• This chart is organized in octaves (frequency doubling/halving) starting at 1Hz and going higher (2,4,8, etc) and

lower (1/2, 1/4, etc). The octave is a natural way to represent frequency.

• Frequency increases in the upward direction. and wrap around from far right to far left.

• There is no limit to either end of this chart, however, due to limited space, only the “known" items have been shownhere. A frequency of 0Hz is the lowest possible frequency but the method of depicting octaves used here does notallow for ever reaching 0Hz, only approaching it. Also, by the definition of frequency (Cycles per second), there isno such thing as negative frequency.

• Values labels: Frequency in Hertz, Wavelength in meters, Energy in electronVolts.

Gamma Rays• Gamma radiation is the highest energy radiation (up to ≈ 10

20 eV) that has been measured. At this energy, theradiation could be from gamma-rays, protons, electrons, or something else.

• Alpha, beta, and delta radiation are not electromagnetic but are actually parts of the atom being released from aradioactive element. In some cases this can cause gamma radiation. These are not to be confused with brain wavesof similar names.

Ultraviolet Light (UV)• UV light is beyond the range of human vision. A bumblebee can see light in the UVA range which helps them

identify certain flowers.

• Short-term UV-A exposure causes sun-tanning which helps to protect against sunburn. Exposure to UV-B isbeneficial to humans by helping the skin produce vitamin D. Excessive UV exposure causes skin damage. UV-C isharmful to humans but is used as a germicide.

• The Sun produces a wide range of wavelengths including all the UV light, however, UVB is partially filtered by theozone layer and UVC is totally filtered out by the earth’s atmosphere.

Emission and Absorption• As EMR passes through elements, certain wavelength bands get absorbed and some new ones get emitted. This

absorption and emission produces characteristic spectral lines for each element which are useful in determining themakeup of distant stars. These lines are used to prove the red-shift amount of distant stars.

• When a photon hits an atom it may be absorbed if the energy is just right. The energy level of the electron is raised– essentially holding the radiation. A new photon of specific wavelength is created when the energy is released.The jump in energy is a discrete step and many possible discrete levels of energy exist in an atom.

• Johann Balmer created this formula defining the photon emissionwavelength (λ); where m is the initial electron energy level integernumber and n is the final electron energy level integer number:

λ = 364.56nm(

m2

m2− n2

)

• Much of the interstellar matter is made of the simplest atom hydrogen. The hydrogen visible-spectrum emissionand absorption lines are shown below:

Hα Hβ Hγ Hδ Hǫ

Hζ

Hη

Hθ

Emission line

Absorption lineBalmer series name

Pow

er

Wavelength

White Hot

Red Hot

HotCMB

• Max Planck determined the relationshipbetween the temperature of an object andits radiation profile; where Rλ is the radi-ation power, λ is the wavelength, T is thetemperature:

Rλ =37418

λ5ǫ

(

14388λT

− 1

)

Visible Spectrum• The range of EMR visible to humans is called “Light". The visible spectrum also closely resembles the range of

EMR that filters through our atmosphere from the Sun.

• Other creatures see different ranges of visible light; for example bumble-bees can see ultraviolet light and dogs havea different response to colors than do humans.

• The sky is blue because our atmosphere scatters light and the shorter wavelength blue gets scattered the most. Itappears that the entire sky is illuminated by a blue light but in fact that light is scattered from the Sun. The longerwavelengths like red and orange move straight through the atmosphere which makes the Sun look like a brightwhite ball containing all the colors of the visible spectrum.

• Interestingly, the visible spectrum covers approximately one octave (doubling/halving of frequency).

• Astronomers use filters to capture specific wavelengths and reject unwanted wavelengths. The major astronomical(visual) filter bands are depicted as X

Light Amplification by Stimulated Emission of Radiation (LASER)• A LASER is a device that produces coherent monochromatic EMR of high intensity .

• With proper equipment, any EMR like visible light, ultraviolet, x-rays, and gamma rays can be made to operate likea LASER. A MASER functions similarly to the LASER and is made with with microwaves and radio waves.

Television (TV)• Terrestrial broadcast TV uses the VHF and UHF ranges (30MHz - 3GHz) 05 .

• Satellite television is transmitted in the C-band (4 - 8 GHz) 05 and Ku-band (12 - 18 GHz) ut where one ofmany satellites is shown. To eliminate interference, the stations are broadcast in alternating polarities, for example,Ch 1 is vertical and Ch 2 is horizontal and vice versa on neighboring satellites.

• TV channels transmitted through cable (CATV) are shown as 05 . CATV channels starting with “T-" are channelsfed back to the cable TV station (like news feeds).

• Air and cable analog TV stations are broadcast withthe separate video, color, and audio frequency carriersgrouped together in a channel band as follows:

6MHz

u u u1.25MHz 3.58MHz

4.5MHz

Video Color Audio

• The 15.7 kHz horizontal sweep signal is a common contaminant to VLF listening .

• Digital compression methods are used for HDTV broadcasts in order to pack more channels into the same 6MHzbandwidth as analog TV.

Radio Bands• The radio spectrum (ELF to EHF) is populated by many more items than can be shown on this chart. Only a

small sampling of the bands used around the world are shown. Each country has its own rules and regulations forallotting bands in this region. FCC , CRTC , OFCOM , BNA , CII ...

• Communication by EMR is done by modulating the carrier waveform:

No modulation Amplitude Modulation (AM) Frequency Modulation (FM)

• RAdio Detecting And Ranging (RADAR) uses microwaves to detect the distance and speed of objects.

• Citizens Band Radio (CB) contains 40 stations between 26.965 - 27.405MHz CB . Schumann resonances areproduced in the cavity between the Earth and the ionosphere S . Hydrogen gas emits radio band EMR at 21cmH . Time / frequency standards shown as . Other individual frequencies are represented as icons:

xxHz Submarine P Pager GMRS General Mobile Radio Service

xxm Ham / international W Weather Short wave

FRS Family Radio Service Wireless Mic. Cellular Phones 3G 4G 5G

International Telecommunication Union (ITU) standard morse code.

A K U 0 &B L V 1 -C M W 2 =D N X 3 ,E O Y 4 ’F P Z 5 +G Q 6 ?H R . 7 "I S @ 8 /

J T : 9 SOS

Sound• Although sound, ocean waves, and heartbeats are not electromagnetic, they are included on this

chart as a frequency reference. Other properties of electromagnetic waves are different from soundwaves.

• Sound waves are caused by an oscillating compression of molecules. Sound cannot travel in a vacuumsuch as outer space.

• The speed of sound in air at sea level is 1240kph (770mph), and much faster in water at 5328kph(3311mph).

• Humans can only hear sound between ≈20Hz to ≈20kHz. Some bats can hear sound up to 200kHz.

• Infrasound (below 20Hz) can be sensed by internal organs and touch. Frequencies in the 0.2Hz rangeare often the cause of motion sickness.

• The 88 piano keys of the Equal Temperament scale are accurately located on the frequency chart.

The musical note A (A4 or A440 at 440Hz) is depicted on the chart as A4 .

• Over the ages people have striven to divide the continuous audio frequency spectrum into individualmusical notes that have harmonious relationships besides the octave. Microtonal musicians studyvarious scales. One recent count lists 4700 different musical scales.

Gravitational Waves• Gravity is the mysterious force which holds large objects together and binds our planets, stars, and

galaxies together. No links have been established between gravity and electromagnetic radiation orthe other physical forces like; the Weak force, the Electromagnetic force, and the Strong force.

• Gravity is theorized to warp space and time. In fact, gravity is responsible for bending light asobserved by the gravity-lens example of distant stars and galaxies.

• “Gravitational waves” appear as ripples in space-time travelling at the speed of light. Long theorized,a gravitational wave was first detected in 2015, and was caused by the merger of two black holes1.4 billion light years away.

Brain Waves• By connecting electrodes from the human head to an electroencephalograph (EEG), it is possible to

measure very small cyclic electrical signals.

• There has been much study on this topic, but like all effects on humans, the findings are not assound as the science of materials.

• Generally, lower brain wave frequencies relate to sleep, and the higher frequencies relate to alertness.

• Devices have been made for measuring and stimulating brain waves to achieve a desired state.

Systeme International d’Unites prefixes (SI unit prefixes)

Symbol Prefix Exp. Name Multiplier

Y yotta 1024 Septillion 1,000,000,000,000,000,000,000,000Z zetta 1021 Sextillion 1,000,000,000,000,000,000,000E exa 1018 Quintillion 1,000,000,000,000,000,000P peta 1015 Quadrillion 1,000,000,000,000,000T tera 1012 Trillion 1,000,000,000,000G giga 109 Billion 1,000,000,000M mega 106 Million 1,000,000k kilo 103 Thousand 1,000

100 1m milli 10-3 Thousandth 0.001µ micro 10-6 Millionth 0.000 001n nano 10-9 Billionth 0.000 000 001p pico 10-12 Trillionth 0.000 000 000 001f femto 10-15 Quadrillionth 0.000 000 000 000 001a atto 10-18 Quintillionth 0.000 000 000 000 000 001z zepto 10-21 Sextillionth 0.000 000 000 000 000 000 001y yocto 10-24 Septillionth 0.000 000 000 000 000 000 000 001

Measurements on this chart

Symbol Name Value

c Speed of Light 2.997 924 58 ×108 ms−1

h Planck’s Constant 6.626 1 ×10−34 J·s

h Planck’s Constant (freq) 1.054 592 ×10−34 J·s

f Frequency (cycles / second) Hzλ Wavelength (meters) m

E Energy (Joules) J (6.24 ×1018 eV)

Formulas

E = h · f

λ = cf

f = cλ

1A = 0.1nm

1nm = 10A

Sourcesof EMR

Sourcesof EMR

HumanBrain

PowerLines

(50,60Hz)

InductionHeating

Cellphone

Micro-waveoven

Radar

Lightbulb

People

Radiotower

X-Raymachines

Radioac-tive

elements

Sizes ofEMR

Sizes ofEMR

Earth12,756

km

FootballField100m

House12m

Football308mm

People1.8m

HoneyBee

1.2cm

SingleCell10µm

WaterMolecule0.3 nm

Bacteria3µm -800nm

Virus17−

300nm

GAM

MA

RAYS

X-R

AYS

ULT

RAVIO

LET

VISIBLE

INFRARED

MIC

RO

WAVE

RAD

IOW

AVES

Frequency Wavelength Energy

0.1Hz

δ (Delta brain waves)

3Hz

θ (Theta brain waves)

8Hz8Hzα (Alpha brain waves)

12Hz β (Low Beta brain waves)15Hzβ (Mid Beta brain waves) 18Hz

β (High Beta brain waves)30Hz

γ (Gamma brain waves)

S

S

S

S

SS

S50Hz Power

v=

100Hz Lights

p=

60Hz Power

v=

120Hz Lights

p=

150Hz3rd harmonic

180Hz3rd harmonic

400Hz

Airplane Power

AM Radio

540600

700800

90010001100 1200 1300 1400 1500 1600

A4

Ground Wave Emergency Network

Europe and Asia AM

EU&Asia AM

RadiolocationMaritime MobileMaritime Mobile

Navigational Beacons

Navigational Beacons

Marine RadioMarine Radio

Morse code

SOSBeacons

X-Band BeaconsMarine

MarineSOS Marine AeronauticalAero

LORAN-C navigation

RadionavigationMaritime Mobile

Maritime Mobile

Maritime Mobile

Maritime Mobile

Maritime MobileMaritime Mobile

MarineMarine

Aero

Marine Aero

Marine Aero International Intnl. and relaysAero Marine

MarineAero Marine

Remote Ctrl

P PP

PP

PPPP

Cordless Phone (Out)(In)

FRSGMRS

Babymon.

CB

23

45

6

7 8 9 10 11 12 13

14 15 16 17 18 19 20 21 22 23 2425 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 6869 7071 727374757677787980818283

AeronauticalSOSFM Radio

87.7 92.1 96.1 100.1 104.1 107.9

Marine Mobile

MilitarySOS

Military

GovSOS

160 Meters Ham Radio120m Tropics

90m80m Ham Radio

60mTropics

49m40m Ham

25m22m 20m 19m

16m15m 13m

11m 10m Ham

6m Ham Radio

2m

11

4m

3/4m HamMicrowave P-band (Previous)

u

1GHzMicrowave L-band (Long)

H

T-7

T-8

T-8

T-9

T-10

T-11T-12

T-13T-14

23

405

0695

9697

98 99

07 08 09 10 11 12 13

14 1516 17 18 19 20 21 22

23 24 25 26 27 28 29 30 31

32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 7676 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 100

158

W

W W

u2GHz

Microwave S-band (Short) u

4GHz

Microwave C-band (Compromise)

W-LAN

Wireless LAN

ITFS

0102

0304

0506

0708

0910

1112

1314

1516

1718

1920

2122

2324

u8GHz

Microwave X-band (X marks the spot) u12.5GHz

Microwave Ku-band (Kurtz Under)u18GHz Microwave K-band (Kurtz)

ut ut ut ut ut ut ut ut ut ut ut ut ut ut ut ut

ut ut ut ut ut ut ut ut ut ut ut ut ut ut ut utKu-band TV

ut ut ut ut ut ut ut ut ut ut ut ut ut ut ut ut

ut ut ut ut ut ut ut ut ut ut ut ut ut ut ut ut

Water absorption 22GHz

Cordless phone 2.4GHz 2.45GHz Microwave Oven

u27.25GHz Microwave Ka-band (Kurtz Above)u

36GHz Microwave Q-band u46GHz Microwave V-band u

56GHz

Microwave W-band

O2 absorption 60GHzu

100GHz

O2 absorption 118.75GHz

Water absorption 183GHz

u100µm3THz

Far Infrared

u30µm

Thermal Infrared

u3µm

Near InfraredEDFAEDFA

Datacom

Telecom

u u u u u u u u u u u u u u u u u u u u u u uu u u u u u u u u uu u u u u

VISIBLE SPECTRUMVISIBLE SPECTRUM

B

VR

I

J

H

K

400nm UV-AUV-A1

UV-A2340nm 320 315nm

UV-B 280nmUV-C

EUV (Extreme Ultraviolet)

100nm

10nm

Soft XRay

1nm

Hard XRay

15.2Gm 86.3 aeV 22.1mHz 12.8Gm 103 aeV 26.3mHz 10.8Gm 122 aeV 31.2mHz31.2mHz 9.05Gm 145 aeV 37.2mHz 7.61Gm 173 aeV 44.2mHz 6.40Gm 205 aeV 52.6mHz 5.38Gm 244 aeV 62.5mHz62.5mHz 4.53Gm 290 aeV 74.3mHz 3.81Gm 345 aeV 88.4mHz 3.20Gm 410 aeV 105mHz 2.69Gm 488 aeV 125mHz125mHz 2.26Gm 580 aeV 149mHz 1.90Gm 690 aeV 177mHz 1.60Gm 821 aeV 210mHz 1.35Gm 976 aeV 250mHz250mHz 1.13Gm 1.16 feV 297mHz 952Mm 1.38 feV 354mHz 800Mm 1.64 feV 420mHz 673Mm 1.95 feV 500mHz500mHz 566Mm 2.32 feV 595mHz 476Mm 2.76 feV 707mHz 400Mm 3.28 feV 841mHz 337Mm 3.90 feV 1.00Hz1.00Hz 283Mm 4.64 feV 1.19Hz 238Mm 5.52 feV 1.41Hz 200Mm 6.56 feV 1.68Hz 168Mm 7.81 feV 2.00Hz2.00Hz 141Mm 9.28 feV 2.38Hz 119Mm 11.0 feV 2.83Hz 100Mm 13.1 feV 3.36Hz 84.1Mm 15.6 feV 4.00Hz4.00Hz 70.7Mm 18.6 feV 4.76Hz 59.5Mm 22.1 feV 5.66Hz 50.0Mm 26.3 feV 6.73Hz 42.1Mm 31.2 feV 8.00Hz8.00Hz 35.4Mm 37.1 feV 9.51Hz 29.7Mm 44.2 feV 11.3Hz 25.0Mm 52.5 feV 13.5Hz 21.0Mm 62.5 feV 16.0Hz16.0Hz 17.7Mm 74.3 feV 19.0Hz 14.9Mm 88.3 feV 22.6Hz 12.5Mm 105 feV 26.9Hz 10.5Mm 125 feV 32.0Hz32.0Hz 8.84Mm 149 feV 38.1Hz 7.44Mm 177 feV 45.3Hz 6.25Mm 210 feV 53.8Hz 5.26Mm 250 feV 64.0Hz64.0Hz 4.42Mm 297 feV 76.1Hz 3.72Mm 353 feV 90.5Hz 3.13Mm 420 feV 108Hz 2.63Mm 500 feV 128Hz128Hz 2.21Mm 594 feV 152Hz 1.86Mm 707 feV 181Hz 1.56Mm 840 feV 215Hz 1.31Mm 999 feV 256Hz256Hz 1.11Mm 1.19 peV 304Hz 929 km 1.41 peV 362Hz 782 km 1.68 peV 431Hz 657 km 2.00 peV 512Hz512Hz 553 km 2.38 peV 609Hz 465 km 2.83 peV 724Hz 391 km 3.36 peV 861Hz 329 km 4.00 peV 1.02 kHz1.02 kHz 276 km 4.75 peV 1.22 kHz 232 km 5.65 peV 1.45 kHz 195 km 6.72 peV 1.72 kHz 164 km 7.99 peV 2.05 kHz2.05 kHz 138 km 9.51 peV 2.44 kHz 116 km 11.3 peV 2.90 kHz 97.7 km 13.4 peV 3.44 kHz 82.2 km 16.0 peV 4.10 kHz4.10 kHz 69.1 km 19.0 peV 4.87 kHz 58.1 km 22.6 peV 5.79 kHz 48.8 km 26.9 peV 6.89 kHz 41.1 km 32.0 peV 8.19 kHz8.19 kHz 34.5 km 38.0 peV 9.74 kHz 29.0 km 45.2 peV 11.6 kHz 24.4 km 53.8 peV 13.8 kHz 20.5 km 64.0 peV 16.4 kHz16.4 kHz 17.3 km 76.1 peV 19.5 kHz 14.5 km 90.4 peV 23.2 kHz 12.2 km 108 peV 27.6 kHz 10.3 km 128 peV 32.8 kHz32.8 kHz 8.64 km 152 peV 39.0 kHz 7.26 km 181 peV 46.3 kHz 6.11 km 215 peV 55.1 kHz 5.13 km 256 peV 65.5 kHz65.5 kHz 4.32 km 304 peV 77.9 kHz 3.63 km 362 peV 92.7 kHz 3.05 km 430 peV 110 kHz 2.57 km 512 peV 131 kHz131 kHz 2.16 km 608 peV 156 kHz 1.82 km 724 peV 185 kHz 1.53 km 860 peV 220 kHz 1.28 km 1.02 neV 262 kHz262 kHz 1.08 km 1.22 neV 312 kHz 908m 1.45 neV 371 kHz 763m 1.72 neV 441 kHz 642m 2.05 neV 524 kHz524 kHz 540m 2.43 neV 623 kHz 454m 2.89 neV 741 kHz 382m 3.44 neV 882 kHz 321m 4.09 neV 1.05MHz1.05MHz 270m 4.87 neV 1.25MHz 227m 5.79 neV 1.48MHz 191m 6.88 neV 1.76MHz 160m 8.19 neV 2.10MHz2.10MHz 135m 9.74 neV 2.49MHz 113m 11.6 neV 2.97MHz 95.4m 13.8 neV 3.53MHz 80.2m 16.4 neV 4.19MHz4.19MHz 67.5m 19.5 neV 4.99MHz 56.7m 23.2 neV 5.93MHz 47.7m 27.5 neV 7.05MHz 40.1m 32.7 neV 8.39MHz8.39MHz 33.7m 38.9 neV 9.98MHz 28.4m 46.3 neV 11.9MHz 23.9m 55.1 neV 14.1MHz 20.1m 65.5 neV 16.8MHz16.8MHz 16.9m 77.9 neV 20.0MHz 14.2m 92.6 neV 23.7MHz 11.9m 110 neV 28.2MHz 10.0m 131 neV 33.6MHz33.6MHz 8.43m 156 neV 39.9MHz 7.09m 185 neV 47.5MHz 5.96m 220 neV 56.4MHz 5.01m 262 neV 67.1MHz67.1MHz 4.22m 312 neV 79.8MHz 3.55m 370 neV 94.9MHz 2.98m 441 neV 113MHz 2.51m 524 neV 134MHz134MHz 2.11m 623 neV 160MHz 1.77m 741 neV 190MHz 1.49m 881 neV 226MHz 1.25m 1.05 µeV 268MHz268MHz 1.05m 1.25 µeV 319MHz 886mm 1.48 µeV 380MHz 745mm 1.76 µeV 451MHz 627mm 2.10 µeV 537MHz537MHz 527mm 2.49 µeV 638MHz 443mm 2.96 µeV 759MHz 373mm 3.52 µeV 903MHz 313mm 4.19 µeV 1.07GHz1.07GHz 264mm 4.98 µeV 1.28GHz 222mm 5.93 µeV 1.52GHz 186mm 7.05 µeV 1.81GHz 157mm 8.38 µeV 2.15GHz2.15GHz 132mm 9.97 µeV 2.55GHz 111mm 11.9 µeV 3.04GHz 93.2mm 14.1 µeV 3.61GHz 78.3mm 16.8 µeV 4.29GHz4.29GHz 65.9mm 19.9 µeV 5.11GHz 55.4mm 23.7 µeV 6.07GHz 46.6mm 28.2 µeV 7.22GHz 39.2mm 33.5 µeV 8.59GHz8.59GHz 32.9mm 39.9 µeV 10.2GHz 27.7mm 47.4 µeV 12.1GHz 23.3mm 56.4 µeV 14.4GHz 19.6mm 67.1 µeV 17.2GHz17.2GHz 16.5mm 79.8 µeV 20.4GHz 13.9mm 94.8 µeV 24.3GHz 11.6mm 113 µeV 28.9GHz 9.79mm 134 µeV 34.4GHz34.4GHz 8.24mm 160 µeV 40.9GHz 6.93mm 190 µeV 48.6GHz 5.82mm 226 µeV 57.8GHz 4.90mm 268 µeV 68.7GHz68.7GHz 4.12mm 319 µeV 81.7GHz 3.46mm 379 µeV 97.2GHz 2.91mm 451 µeV 116GHz 2.45mm 536 µeV 137GHz137GHz 2.06mm 638 µeV 163GHz 1.73mm 759 µeV 194GHz 1.46mm 902 µeV 231GHz 1.22mm 1.07meV 275GHz275GHz 1.03mm 1.28meV 327GHz 866 µm 1.52meV 389GHz 728 µm 1.80meV 462GHz 612 µm 2.15meV 550GHz550GHz 515 µm 2.55meV 654GHz 433 µm 3.03meV 777GHz 364 µm 3.61meV 925GHz 306 µm 4.29meV 1.10THz1.10THz 257 µm 5.10meV 1.31THz 216 µm 6.07meV 1.55THz 182 µm 7.22meV 1.85THz 153 µm 8.58meV 2.20THz2.20THz 129 µm 10.2meV 2.62THz 108 µm 12.1meV 3.11THz 91.0 µm 14.4meV 3.70THz 76.5 µm 17.2meV 4.40THz4.40THz 64.3 µm 20.4meV 5.23THz 54.1 µm 24.3meV 6.22THz 45.5 µm 28.9meV 7.40THz 38.3 µm 34.3meV 8.80THz8.80THz 32.2 µm 40.8meV 10.5THz 27.1 µm 48.6meV 12.4THz 22.7 µm 57.7meV 14.8THz 19.1 µm 68.7meV 17.6THz17.6THz 16.1 µm 81.7meV 20.9THz 13.5 µm 97.1meV 24.9THz 11.4 µm 115meV 29.6THz 9.56 µm 137meV 35.2THz35.2THz 8.04 µm 163meV 41.8THz 6.76 µm 194meV 49.8THz 5.69 µm 231meV 59.2THz 4.78 µm 275meV 70.4THz70.4THz 4.02 µm 327meV 83.7THz 3.38 µm 388meV 99.5THz 2.84 µm 462meV 118THz 2.39 µm 549meV 141THz141THz 2.01 µm 653meV 167THz 1.69 µm 777meV 199THz 1.42 µm 924meV 237THz 1.20 µm 1.10 eV 281THz281THz 1.01 µm 1.31 eV 335THz 845 nm 1.55 eV 398THz 711 nm 1.85 eV 473THz 598 nm 2.20 eV 563THz563THz 503 nm 2.61 eV 669THz 423 nm 3.11 eV 796THz 355 nm 3.70 eV 947THz 299 nm 4.39 eV 1.13PHz1.13PHz 251 nm 5.23 eV 1.34PHz 211 nm 6.22 eV 1.59PHz 178 nm 7.39 eV 1.89PHz 149 nm 8.79 eV 2.25PHz2.25PHz 126 nm 10.5 eV 2.68PHz 106 nm 12.4 eV 3.18PHz 88.9 nm 14.8 eV 3.79PHz 74.7 nm 17.6 eV 4.50PHz4.50PHz 62.8 nm 20.9 eV 5.36PHz 52.8 nm 24.9 eV 6.37PHz 44.4 nm 29.6 eV 7.57PHz 37.4 nm 35.2 eV 9.01PHz9.01PHz 31.4 nm 41.8 eV 10.7PHz 26.4 nm 49.7 eV 12.7PHz 22.2 nm 59.1 eV 15.1PHz 18.7 nm 70.3 eV 18.0PHz18.0PHz 15.7 nm 83.6 eV 21.4PHz 13.2 nm 99.4 eV 25.5PHz 11.1 nm 118 eV 30.3PHz 9.34 nm 141 eV 36.0PHz36.0PHz 7.85 nm 167 eV 42.8PHz 6.60 nm 199 eV 51.0PHz 5.55 nm 237 eV 60.6PHz 4.67 nm 281 eV 72.1PHz72.1PHz 3.93 nm 335 eV 85.7PHz 3.30 nm 398 eV 102PHz 2.78 nm 473 eV 121PHz 2.33 nm 563 eV 144PHz144PHz 1.96 nm 669 eV 171PHz 1.65 nm 796 eV 204PHz 1.39 nm 946 eV 242PHz 1.17 nm 1.13 keV 288PHz288PHz 982 pm 1.34 keV 343PHz 826 pm 1.59 keV 408PHz 694 pm 1.89 keV 485PHz 584 pm 2.25 keV 576PHz576PHz 491 pm 2.68 keV 686PHz 413 pm 3.18 keV 815PHz 347 pm 3.78 keV 969PHz 292 pm 4.50 keV 1.15 EHz1.15 EHz 245 pm 5.35 keV 1.37 EHz 206 pm 6.36 keV 1.63 EHz 174 pm 7.57 keV 1.94 EHz 146 pm 9.00 keV 2.31 EHz2.31 EHz 123 pm 10.7 keV 2.74 EHz 103 pm 12.7 keV 3.26 EHz 86.8 pm 15.1 keV 3.88 EHz 73.0 pm 18.0 keV 4.61 EHz4.61 EHz 61.4 pm 21.4 keV 5.48 EHz 51.6 pm 25.5 keV 6.52 EHz 43.4 pm 30.3 keV 7.76 EHz 36.5 pm 36.0 keV 9.22 EHz

0.1nm

Gamma Ray

∞eV

1

∞m

∞Hz

1

∞eV

∞m

1

∞Hz

13.6kHz 14.7kHz15.5kHz

17.8kHz 18.6kHz21.4kHz 22.3kHz

b b b b b b b b b b b b b b b b b b b b b b b b b b b b b b b b b b

24kHz30.0kHz

40.75kHz

76Hz

GPSCivil

GPSMil.

GPSNuc.

GPSIon.

GPSSoL

GPSSpace

Cs-133 9,192,631,770Hz SI-time standard

ULF

Ultra

Low

Fre

quen

cy

3H

z

ELF

Ext

rem

ely

Low

Fre

quen

cy

30H

z

VLF

Ver

yLow

Fre

quen

cy

3kH

z

LF

Low

Fre

quen

cy

30kH

z

MF

Med

ium

Fre

quen

cy

300kH

z

HF

Hig

hFre

quen

cy

3M

Hz

VH

FVer

yH

igh

Fre

quen

cy

30M

Hz

UH

FU

ltra

Hig

hFre

quen

cy

300M

Hz

SH

FSuper

Hig

hFre

quen

cy

3G

Hz

EH

FExt

rem

ely

Hig

hFre

quen

cy

30G

Hz

300G

Hz

Mic

rowave

mm

-band

Mic

rowave

µmm

−band

Ter

aher

tzra

ys

3T

Hz

400nm 300nm200nm

100nm

10nm

NUV

MUV

FUV

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Cosmic Microwave Background Radiation (CMB)• CMB radiation is the leftover heat from the hot early universe, which last scattered about 400,000 years

after the Big Bang.

• CMB permeates the entire universe at a temperature of 2.725 ± 0 001K.

• Arno Penzias and Robert Wilson accidentally discovered CMB while working for Bell Telephone Labora-tories in 1965.

• The intensity is measured in Mega Jansky (Jy) per steradian.

1Jy = 10−26W/m2/Hz

• Close examination of slight CMB intensity variations in differentparts of the sky help cosmologists study the formation of galaxies.

WMAP photo by NASA

The Electromagnetic Radiation Spectrum

Electromagnetic Radiation (EMR)• EMR is emitted in discrete units called photons but has properties of

waves. EMR can be created by the oscillation or acceleration of electricalcharge or magnetic field. EMR travels through space at the speed of light(c = 2.99792458× 10

8 ms−1 ). EMR consists of an oscillating electricaland magnetic field at right angles to each other and spaced at a particularwavelength.

Electric Field Strength

-E

Magnetic Field Strength

-BSource

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Wave Nature

Source

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Particle Nature

• The particle nature is exhibited when a dimly lit solar cell emits individualelectrons. The wave nature is demonstrated by the double slit experimentthat shows cancellation and addition of waves.

• The wavelength of EMR is changed when the source is receding or ap-proaching. Red-shift makes high-speed receding stars and galaxies appearmore red.

Polarization• EMR will travel through space

linearly with no rotation, or el-liptically or circularly where itsaxis of electrical and magneticfluctuations are rotated. Theelectrical field is shown here:

Linear Elliptical Circular

• Some crystals cause the photon to rotate its polarization.

• Receivers that expect polarized photons will not accept photons that are in otherpolarities. (ex. satellite dish receivers have horizontal and vertical polarity positions).

• Polarized filters (like PolaroidTM sunglasses) can be used todemonstrate polarized light. One filter will only let photonsthat have one polarity through. Two overlapping filters atright angles will almost completely block the light that exits.The Dirac three polarizers experiment shows that a third filterinserted between the first two at 45◦ allows some light to comeout the end of all three filters.

• Reflections from an electrical insulator are polarized. Conductive reflectors do notpolarize EMR.

• Light from a rainbow is polarized due to the reflection inside the water droplets.

• Moonlight is slightly polarized. Rotating a polarized sunglass lens causes the moon-light to dim and brighten slightly.

Refraction• Refraction, or bending of

EMR, is dependent on wave-length. All wavelengths ofEMR can be refracted byusing the proper materials.White light can be spread byrefraction into a spectrum ofits composite colors with aglass prism.

Glass prism

• Convex and concavelenses make objectsappear closer and furtherand are used to cor-rect far-sightedness andnear-sightedness.

Convex Concave

• Heavy objects like densegalaxies, stars, and largeplanets cause light to benddue to gravitational lensingas seen here in galaxy clus-ter Abell 2218: S

TScI

Reflection• Reflection of EMR is dependent on wave-

length as demonstrated when visible lightand radio waves bounce off objects thatX-Rays would pass through. Microwaves,which have a large wavelength comparedto visible light, will bounce off metalmesh in a microwave oven whereas vis-ible light will pass through.

Sourceθi θr

Reflector

• EMR of any wavelength can be reflected,however, the reflectivity of a materialdepends on many factors including thewavelength of the incident beam.

• The angle of incidence (θi) and angle ofreflection (θr) are the same.

Infrared Radiation (IR)• IR is sensed by humans as heat and is below the range of human

vision. All creatures emit IR, and snakes can detect it.

• IR remote control signals are invisible to the human eye but canbe detected by some electronic cameras.

•

NASA/IPAC

Night vision scopes/gog-gles use a special camerathat senses IR and con-verts the image to visiblelight. Some IR camerasemploy an IR lamp to helpilluminate the view.

• A demonstration of IR is to hold a metal bowl in front of yourface. The IR emitted by your body will be reflected back usingthe parabolic shape of the bowl and you will feel the heat.

• IR LASERs are used for cutting material.

• Fiber-optic based infrared communication signals are sometimesamplified with Erbium-Doped Fiber Amplifiers EDFA

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