The Electromagnetic Radiation Spectrum
1.13 PHz
281 THz
5.36 PHz
20.9 eV
141 THz
70.4 THz
503 nm
VISIBLE SPECTRUM
669 THz
2.61 eV
35.2 THz
17.6 THz
16.1 µm
18.0 PHz
26.4 nm
49.7 eV
22.2 nm
7.57 PHz
37.4 nm
35.2 eV
9.01 PHz
29.6 eV
52.8 nm
t)
EUV (Extreme Ultraviole
44.4 nm
6.37 PHz
24.9 eV
74.7 nm
17.6 eV
4.50 PHz
3.11 eV
Datacom I
167 THz
653 meV
8.80 THz
777 meV
One Cycle
Per Second
Human
Brain
Sizes of
EMR
515 µm
1.03 mm
2.06 mm
4.12 mm
36GHz
5.10 meV
2.55 meV
1.28 meV
638 µeV
319 µeV
Telecom
5.23 THz
2.62 THz
24.3 meV
108 µm
100µm
3THz
3.11 THz
V
me
12.1
777 GHz
3.03 meV
433 µm
654 GHz
1.55 THz
6.07 meV
216 µm
1.31 THz
6.22 THz
54.1 µm
389 GHz
1.52 meV
866 µm
z
GH
183
n
tio
Water absorp
327 GHz
1.73 mm
163 GHz
194 GHz
759 µeV
4.39 eV
VISIBLE SPECTRUM
2.20 eV
598 nm
1.10 eV
4.78 µm
275 meV
70.4 THz
5.69 µm
59.2 THz
9.56 µm
137 meV
11.4 µm
29.6 THz
35.2 THz
115 meV
549 meV
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 the makeup 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 levels of energy exist in an atom.
141 THz
• Johann Balmer created this formula defining the photon emission wavelength (λ);
where m is the initial electron energy level and n is the final electron energy level:
"
!
m2
λ = 364.56nm
2
2
m −n
• Much of the interstellar matter is made of the simplest atom hydrogen. The hydrogen
visible-spectrum emission and absorption lines are shown below:
Hη
Emission line
57.7 meV
19.1 µm
68.7 meV
22.7 µm
14.8 THz
17.6 THz
38.3 µm
34.3 meV
45.5 µm
7.40 THz
8.80 THz
28.9 meV
3.70 THz
76.5 µm
17.2 meV
14.4 meV
153 µm
8.58 meV
182 µm
1.85 THz
2.20 THz
7.22 meV
306 µm
4.29 meV
364 µm
925 GHz
1.10 THz
3.61 meV
2.15 meV
462 GHz
612 µm
1.46 mm
902 µeV
231 GHz
1.07 meV
1.22 mm
n 118.75GHz
tio
orp
O2 abs
451 µeV
116 GHz
137 GHz
536 µeV
2.45 mm
O2 absorption 60GHz
4.90 mm
268 µeV
White Hot
Red Hot
Hot
CMB
Frequency
Sp
ace
Hγ
Hδ H% Hθ
Hζ
• Max Planck determined the relationship between
the temperature of an object and its radiation profile; where Rλ is the radiation power, λ is the
wavelength, T is the temperature:
! 37418
"
Rλ =
14388 − 1
5
λT
λ '
E = Electric Field Strength
B = Magnetic Field Strength
Wave Nature
• The wave nature of EMR is demonstrated by the famous double slit
experiment that shows cancelling and addition of waves.
• Much of the EMR properties are based on theories since we can only
see the effects of EMR and not the actual photon or wave itself.
• Albert Einstein theorized that the speed of light is the fastest that
anything can travel. So far he has not been proven wrong.
• EMR can have its wavelength changed if the source is receding or
approaching as in the red-shift example of distant galaxies and stars
that are moving away from us at very high speeds. The emitted
spectral light from these receding bodies appears more red than it
would be if the object was not moving away from us.
• We only have full electronic control over frequencies in the microwave
range and lower. Higher frequencies must be created by waiting for
the energy to be released from elements as photons. We can either
pump energy into the elements (ex. heating a rock with visible EMR
and letting it release infrared EMR) or let it naturally escape (ex.
uranium decay).
• We can only see the visible spectrum. All other bands of the spectrum
.
are depicted as hatched colours
Système International d’unité prefixes (SI unit prefixes)
Symbol Name Exp.
Multiplier
Y
Z
E
P
T
G
M
k
yotta
zetta
exa
peta
tera
giga
mega
kilo
m
µ
n
p
f
a
z
y
milli
micro
nano
pico
femto
atto
zepto
yocto
1024
1021
1018
1015
1012
109
106
103
100
10−3
10−6
10−9
10−12
10−15
10−18
10−21
10−24
• The intensity is measured in Mega Jansky (Jy) per steradian.
1Jy = 10−26 W/m2 /Hz
65 GHz
Close examination of slight CMB intensity
variations in different parts of the sky help
cosmologists study the formation of galaxies.
WMAP photo by NASA
1,000,000,000,000,000,000,000,000
1,000,000,000,000,000,000,000
1,000,000,000,000,000,000
1,000,000,000,000,000
1,000,000,000,000
1,000,000,000
1,000,000
1,000
1
0.001
0.000 001
0.000 000 001
0.000 000 000 001
0.000 000 000 000 001
0.000 000 000 000 000 001
0.000 000 000 000 000 000 001
0.000 000 000 000 000 000 000 001
Measurements on this chart
Name
Symbol
c
h
h̄
f
λ
E
Speed of Light
Planck’s Constant
Planck’s Constant (freq)
Frequency (cycles / second)
Wavelength (meters)
Energy (Joules)
Value
2.997 924 58 ×108 m/s
6.626 1 ×10−34 J · s
1.054 592 ×10−34 J · s
Hz
m
J
Conversions
E = h·f
λ = c
f
1Å = 0.1nm
1nm = 10Å
1Joule = 6.24 ×1018 eV
• CMB was predicted in the 1940’s by Ralph Alpher, George
Gamow and Robert Herman.
• Arno Penzias and Robert Wilson accidentally discovered CMB
while working for Bell Telephone Laboratories in 1965.
Particle Nature
• The particle nature of EMR is exhibited when a solar cell emits individual electrons when struck with very dim light.
• CMB permeates the entire universe at a temperature of 2.725
± 0.001K.
275 GHz
68.7 GHz
Sp
ace
• CMB radiation is the leftover heat from the hot early universe,
which last scattered about 400,000 years after the Big Bang.
600 GHz
CMB
550 GHz
1.80 meV
57.8 GHz
Hβ
Balmer series name
Cosmic Microwave Background Radiation
728 µm
56GHz
Hα
Absorption line
4.40 THz
91.0 µm
Gamma Rays
• Gamma radiation is the highest energy radiation (up to ≈ 10 20 eV)
that has been measured. At this energy, the radiation 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 a radioactive atom. In
some cases this can cause gamma radiation. These are not to be
confused with brain waves of similar names.
Television
• Television is transmitted in the VHF and UHF ranges (30MHz - 3GHz).
• TV channels transmitted over the air are shown as TV .
• TV channels transmitted through cable (CATV) are shown as TV . CATV channels
starting with “T-” are channels fed back to the cable TV station (like news feeds).
• Air and cable TV stations are broadcast with the separate video, colour, and audio
frequency carriers grouped together in a channel band as follows:
6MHz
4.5MHz
1.25MHz
3.58MHz
Video
Colour
Audio
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
127
128
129
• A bumblebee can see light in the UVA range which helps them identify certain
flowers.
281 THz
231 meV
226 µeV
• The sun produces a wide range of frequencies including all the ultraviolet light,
however, UVB is partially filtered by the ozone layer and UVC is totally filtered out
by the earth’s atmosphere.
J
2.84 µm
125
126
• The CIE originally divided UVA and UVB at 315nm, later some photo-dermatologists
divided it at 320nm.
563 THz
2.39 µm
122
123
124
121
120
119
118
117
116
108
107
106
105
• Short-term UV-A exposure causes sun-tanning which helps to protect against sunburn. Exposure to UV-B is beneficial to humans by helping the skin produce vitamin
D. Excessive UV exposure causes skin damage. UV-C is harmful to humans but is
used as a germicide.
V
190 µeV
6.93 mm
urtz Above)
40.9 GHz
Microwave Ka-band (K
µeV
160
25GHz
mm
4
27.
Hz
8.2
22G
n
tio
orp
abs
ter
34.4 GHz
34.4 GHz
Wa
134 µeV
9.79 mm
GHz
9
z)
28.
urt
(K
and
µeV
K-b
ve
113
Microwa
11.6 mm
18GHz
24.3 GHz
94.8 µeV
13.9 mm
urtz Under)
z
GH
4
20.
Microwave Ku-band (K
79.8 µeV
16.5 mm
Hz
5G
17.2 GHz
17.2 GHz
12.
67.1 µeV
rks the spot)
19.6 mm
z SI-time standard
14.4 GHz
Microwave X-band (X ma
µeV
4
Cs-133 9,192,631,770H
56.
23.3 mm
12.1 GHz
47.4 µeV
8GHz
27.7 mm
z
GH
2
10.
39.9 µeV
romise)
32.9 mm
mp
(Co
and
C-b
ve
8.59 GHz
8.59 GHz
wa
Micro
33.5 µeV
39.2 mm
2 GHz
7.2
N
µeV
2
LA
28.
ss
Wirele
46.6 mm
4GHz
6.07 GHz
22 24
23.7 µeV
12 14 16 18 20
55.4 mm
02 04 06 08 10
z
GH
1
5.1
21 23
µeV
9
11 13 15 17 19
19.
09
07
05
mm
)
03
9
ort
01
65.
ITFS
4.29 GHz
4.29 GHz
Microwave S-band (Sh
16.8 µeV
LAN
78.3 mm
Water absorption W- Microwave Oven
3.61 GHz
µeV
1
14.
93.2 mm
Cordless phone
3.04 GHz
2.45GHz
11.9 µeV
2.4GHz
111 mm
2GHz
z
GH
5
3G
2.5
3G
9.97 µeV
CP
GPS
132 mm
CP
2.15 GHz
2.15 GHz
3G
µeV
8
8.3
L1
157 mm
1.81 GHz
H
GPS
Microwave L-band (Long)
GPS
7.05 µeV
186 mm
L2
1GHz
z
GH
2
1.5
L5
µeV
3
83
5.9
76 77 78 79 80 81 82
222 mm
z
69 70 71 72 73 74 75
GH
68
8
67
1.2
66
65
64
63
62
4.98 µeV
56 57 58 59 60 61
264 mm
50 51 52 53 54 55
1.07 GHz
1.07 GHz
44 45 46 47 48 49
4.19 µeV
38 39 40 41 42 43
313 mm
Phone
33 34 35 36 37
32
CellµeV
31
30
MHz
29
94
903
CP
90 91 92 93
25 26 27 28
89
24
88
2
23
87
3.5
22
86
373 mm
81 82 83 84 85
17 18 19 20 21
15 16
14
76 77 78 79 80
759 MHz
74 75 76
3/4 m Ham
ous)
µeV
evi
6
(Pr
2.9
and
69 70 71 72 73
P-b
mm
68
ve
67
443
wa
66
cro
65
Mi
64
63
Gov
62
638 MHz
61
60
59
58
2.49 µeV
57
56
55
54
527 mm
53
52
51
50
537 MHz
537 MHz
49
48
Military
47
2.10 µeV
46
45
44
627 mm
43
42
41
MHz
40
451
39
38
µeV
6
37
1.7
36
35
745 mm
34
33
Military
32
380 MHz
31
30
1 1/4m
29
1.48 µeV
0.3GHz
28
13
27
886 mm
12
26
z
25
11
MH
319
24
10
23
9
µeV
5
13
1.2
8
12
m
5
7
1.0
11
10
268 MHz
268 MHz
09
Marine Mobile
08
1.05 µeV
07
22
1.25 m
2m
21
MHz
226
20
W
19
neV
881
18
1.49 m
17
W
16
190 MHz
741 neV
Aeronautical
1.77 m
dio
Ra
z
FM
MH
160
15
107.9
.1
104
neV
14
623
.1
100
m
1
99
2.1
96.1
98
92.1
134 MHz
134 MHz
7
97
87.
neV
524
m
96
2.51
6
MHz
95
113
5
neV
441
06
2.98 m
4
05
94.9 MHz
Remote Ctrl
370 neV
3
4
3.55 m
z
MH
8
2
79.
3
6m Ham Radio
312 neV
4.22 m
2
67.1 MHz
67.1 MHz
neV
262
T-14
m
5.01
56.4 MHz
T-13
neV
220
5.96 m
T-12
47.5 MHz
185 neV
7.09 m
CB
T-11
10m Ham
z
MH
9
39.
11m
156 neV
8.43 m
33.6 MHz
e
33.6 MHz
Marin
T-10
131 neV
15m 13m
10.0 m
Aero
2 MHz
28.
neV
110
16m
11.9 m
T-9
Marine
23.7 MHz
19m
92.6 neV
20m
14.2 m
z
MH
0
22m
20.
77.9 neV
Marine
25m
16.9 m
Aero
T-8
16.8 MHz
16.8 MHz
65.5 neV
20.1 m
International
Intnl. and relays
14.1 MHz
Aero
neV
Marine
1
55.
23.9 m
T-7
11.9 MHz
46.3 neV
28.4 m
40m Ham
z
MH
8
9.9
Aero
38.9 neV
Marine
33.7 m
49m
8.39 MHz
8.39 MHz
32.7 neV
40.1 m
Aero
7.05 MHz
60m
neV
5
27.
47.7 m
Tropics
5.93 MHz
23.2 neV
Marine
56.7 m
Marine
z
MH
9
4.9
80m Ham Radio
19.5 neV
67.5 m
90m
Aero
4.19 MHz
4.19 MHz
16.4 neV
80.2 m
z
Aeronautical
MH
3
3.5
neV
8
e
13.
Marin
95.4 m
120m Tropics
SOS
2.97 MHz
11.6 neV
Marine
113 m
z
MH
9
2.4
Marine
160 Meters Ham Radio
9.74 neV
135 m
1600
ns
2.10 MHz
aco
2.10 MHz
0
Be
150
neV
9
and
8.1
X-B
0
140
160 m
0
MHz
6
130
1.7
neV
8
0
6.8
120
191 m
1100
1.48 MHz
5.79 neV
1000
227 m
z
MH
5
1.2
900
4.87 neV
AM Radio
270 m
800
1.05 MHz
1.05 MHz
4.09 neV
700
321 m
882 kHz
neV
4
3.4
600
382 m
540
741 kHz
SOS W
2.89 neV
454 m
z
kH
623
Beacons
neV
3
2.4
m
e
540
Morse cod
524 kHz
524 kHz
neV
5
2.0
642 m
kHz
441
ns
aco
Be
l
neV
ona
EU&Asia AM
2
ati
1.7
Navig
763 m
Marine Radio
371 kHz
1.45 neV
908 m
Marine Radio
z
kH
rope and Asia AM
312
Eu
1.22 neV
ns
1.08 km
aco
Be
l
ona
ati
262 kHz
262 kHz
vig
Na
1.02 neV
1.28 km
kHz
220
peV
rk
860
two
y Ne
1.53 km
Ground Wave Emergenc
185 kHz
Maritime Mobile
724 peV
Maritime Mobile
1.82 km
z
kH
156
608 peV
Radiolocation
2.16 km
131 kHz
131 kHz
512 peV
7 km
2.5
LORAN-C navigation
z
kH
110
peV
430
3.05 km
92.7 kHz
362 peV
3.63 km
Maritime Mobile
z
kH
9
77.
Maritime Mobile
304 peV
4.32 km
65.5 kHz
65.5 kHz
peV
256
5.13 km
kHz
1
55.
Hz
peV
75k
215
40.
6.11 km
46.3 kHz
181 peV
7.26 km
30.0kHz
z
kH
0
Maritime Mobile
39.
152 peV
8.64 km
Hz
32.8 kHz
24k
32.8 kHz
z
128 peV
10.3 km
21.4kHz 22.3kH
6 kHz
27.
bile
Mo
me
riti
peV
Ma
z
108
12.2 km
17.8kHz 18.6kH
23.2 kHz
90.4 peV
14.5 km
z
14.7kHz
kH
5
Maritime Mobile
19.
13.6kHz
15.5kHz
76.1 peV
17.3 km
Maritime Mobile
16.4 kHz
16.4 kHz
64.0 peV
km
5
20.
z
kH
n
8
13.
Radionavigatio
peV
8
53.
24.4 km
11.6 kHz
45.2 peV
29.0 km
z
kH
4
9.7
38.0 peV
34.5 km
8.19 kHz
8.19 kHz
32.0 peV
41.1 km
6.89 kHz
peV
9
26.
48.8 km
5.79 kHz
22.6 peV
58.1 km
z
kH
7
4.8
19.0 peV
69.1 km
4.10 kHz
4.10 kHz
16.0 peV
82.2 km
3.44 kHz
peV
4
13.
97.7 km
2.90 kHz
11.3 peV
116 km
z
kH
4
2.4
9.51 peV
138 km
2.05 kHz
2.05 kHz
7.99 peV
164 km
1.72 kHz
peV
2
6.7
195 km
1.45 kHz
5.65 peV
232 km
z
kH
2
1.2
4.75 peV
276 km
1.02 kHz
1.02 kHz
4.00 peV
329 km
861 Hz
peV
6
3.3
391 km
C
724 Hz
2.83 peV
465 km
Hz
609
400Hz
2.38 peV
553 km
512 Hz
512 Hz
Airplane Power
2.00 peV
657 km
431 Hz
peV
8
1.6
782 km
362 Hz
1.41 peV
929 km
Hz
304
1.19 peV
1.11 Mm
180Hz
256 Hz
256 Hz
999 feV
1.31 Mm
3rd harmonic
150Hz
215 Hz
feV
840
1.56 Mm
3rd harmonic
120Hz Lights
181 Hz
707 feV
1.86 Mm
hts
Lig
Hz
Hz
152
100
p=
594 feV
2.21 Mm
128 Hz
128 Hz
p=
500 feV
2.63 Mm
108 Hz
feV
420
76Hz
3.13 Mm
90.5 Hz
60Hz Power
353 feV
3.72 Mm
r
Hz
we
1
Po
z
76.
50H
v=
297 feV
4.42 Mm
64.0 Hz
64.0 Hz
v=
250 feV
5.26 Mm
S
8 Hz
53.
)
feV
ves
wa
210
in
S
6.25 Mm
γ (Gamma bra
45.3 Hz
177 feV
S
30Hz
7.44 Mm
Hz
1
38.
149 feV
)
8.84 Mm
ves
wa
in
S
bra
ta
32.0 Hz
Be
32.0 Hz
β (High
125 feV
10.5 Mm
9 Hz
26.
feV
105
S
) 18Hz
12.5 Mm
22.6 Hz
β (Mid Beta brain waves
88.3 feV
15Hz
14.9 Mm
Hz
0
19.
)
74.3 feV
S
β (Low Beta brain waves
17.7 Mm
12Hz
16.0 Hz
16.0 Hz
62.5 feV
21.0 Mm
13.5 Hz
α (Alpha brain waves)
feV
5
52.
25.0 Mm
11.3 Hz
8Hz
8Hz
44.2 feV
29.7 Mm
S
Hz
1
9.5
feV
1
37.
Mm
35.4
8.00 Hz
8.00 Hz
θ (Theta brain waves)
31.2 feV
42.1 Mm
6.73 Hz
feV
3
26.
50.0 Mm
5.66 Hz
22.1 feV
59.5 Mm
Hz
6
4.7
18.6 feV
70.7 Mm
3Hz
4.00 Hz
4.00 Hz
15.6 feV
84.1 Mm
3.36 Hz
feV
1
13.
100 Mm
2.83 Hz
11.0 feV
119 Mm
Hz
8
2.3
9.28 feV
141 Mm
2.00 Hz
2.00 Hz
7.81 feV
168 Mm
1.68 Hz
feV
6
6.5
200 Mm
1.41 Hz
5.52 feV
238 Mm
Hz
9
1.1
4.64 feV
283 Mm
1.00 Hz
1.00 Hz
δ (Delta brain waves)
3.90 feV
337 Mm
841 mHz
feV
8
3.2
400 Mm
707 mHz
2.76 feV
476 Mm
z
mH
595
2.32 feV
566 Mm
500 mHz
500 mHz
1.95 feV
673 Mm
420 mHz
feV
4
1.6
800 Mm
354 mHz
1.38 feV
952 Mm
z
mH
297
1.16 feV
1.13 Gm
250 mHz
250 mHz
976 aeV
1.35 Gm
210 mHz
aeV
821
1.60 Gm
177 mHz
690 aeV
1.90 Gm
z
mH
149
580 aeV
0.1Hz
2.26 Gm
125 mHz
125 mHz
488 aeV
2.69 Gm
105 mHz
aeV
410
3.20 Gm
88.4 mHz
345 aeV
3.81 Gm
z
mH
3
74.
290 aeV
4.53 Gm
62.5 mHz
62.5 mHz
244 aeV
5.38 Gm
52.6 mHz
aeV
205
6.40 Gm
44.2 mHz
173 aeV
7.61 Gm
z
mH
2
37.
145 aeV
9.05 Gm
1
31.2 mHz
31.2 mHz
Hz
122 aeV
10.8 Gm
∞
26.3 mHz
aeV
∞m
103
12.8 Gm
1
22.1 mHz
86.3 aeV
eV
Energy
15.2 Gm
∞
velength
Wa
ncy
Freque
104
• Ultraviolet light is beyond the range of human vision.
1.13 PHz
118 THz
Microwave V-band
5.82 mm
48.6 GHz
46GHz
Microwave Q-band
299 nm
462 meV
2.91 mm
97.2 GHz
379 µeV
Ultraviolet Light
280nm
UV-B
So
urc
e
-E
2.25 PHz
1.20 µm
100GHz
Microwave W-band
3.46 mm
81.7 GHz
8.79 eV
237 THz
Far Infrared
100
VLF Very Low Frequency
3Hz
Earth
12,756
km
68.7 GHz
257 µm
10.2 meV
12.4 THz
48.6 meV
27.1 µm
10.5 THz
24.9 THz
97.1 meV
13.5 µm
20.9 THz
81.7 meV
49.8 THz
194 meV
6.76 µm
41.8 THz
103
MICROWAVE
Microwave mm-band
EHF Extremely High Frequency
SHF Super High Frequency
HF High Frequency
30Hz
Induction
Heating
ULF Ultra Low Frequency
ELF Extremely Low Frequency
3kHz
30kHz
LF Low Frequency
300kHz
Radio
tower
RADIO WAVES
Football
Field
100m
3MHz
House
12m
30MHz
People
1.8m
137 GHz
Short Wave radio
300MHz
Cell
phone
275 GHz
Long Wave radio
Football
308mm
550 GHz
UHF Ultra High Frequency
Microwave
oven
1.10 THz
VHF Very High Frequency
3GHz
Radar
MF Medium Frequency
Honey
Bee
1.2cm
30GHz
300GHz
Microwave µmm-band
2.20 THz
129 µm
473 THz
1.85 eV
149 nm
924 meV
Thermal Infrared
163 meV
20.4 meV
99.5 THz
388 meV
3.38 µm
83.7 THz
102
3THz
4.40 THz
64.3 µm
3.79 PHz
14.8 eV
3µm
327 meV
40.8 meV
Near Infrared
1.42 µm
199 THz
EDFA EDFA
H
1.69 µm
711 nm
398 THz
1.55 eV
845 nm
9.34 nm
• Values on the chart have been labelled with the following colours: Frequency measured in Hertz, Wavelength measured in meters, Energy measured in electronVolts.
• UVA is subdivided into UVA1 and UVA2 for DNA altering effects at 340nm.
1.89 PHz
7.39 eV
178 nm
1.59 PHz
315nm
320
340nm
UV-A
UV-A2
UV-A1
947 THz
eV
0
3.7
355 nm
796 THz
R
6.22 eV
400nm
423 nm
88.9 nm
3.18 PHz
B
335 THz
1.31 eV
12.7 PHz
100nm
12.4 eV
30µm
32.2 µm
• UV-A, UV-B and UV-C were introduced in the 1930’s by the Commission Internationale de l’Éclairage (CIE, International Commission on Illumination) for photobiological spectral bands.
70.3 eV
115
People
8.04 µm
141 eV
36.0 PHz
4.67 nm
18.7 nm
114
INFRARED
Single
Cell
10µm
4.02 µm
• Physicists have divided ultraviolet light ranges into Vacuum Ultraviolet (VUV), Extreme Ultraviolet (EUV), Far Ultraviolet (FUV), Medium Ultraviolet (MUV), and
Near Ultraviolet (NUV).
473 eV
15.1 PHz
211 nm
1.34 PHz
5.23 eV
2.01 µm
281 eV
72.1 PHz
121 PHz
59.1 eV
106 nm
2.68 PHz
10.5 eV
K
Bacteria
3µm800nm
Sources
of EMR
10.7 PHz
41.8 eV
251 nm
1.01 µm
144 PHz
118 eV
113
Incandescent
light
bulb
563 THz
2.33 nm
563 eV
11.1 nm
25.5 PHz
99.4 eV
112
NUV
300
MUV
1.17 nm
1.13 keV
1.39 nm
242 PHz
288 PHz
946 eV
576 PHz
10nm
30.3 PHz
UV-C
VISIBLE
Power
Lines
(50,60Hz)
126 nm
584 pm
So
urc
e
• Satellite channels broadcast in the C-Band are depicted as TV . These stations are
broadcast in alternating polarities (Ex. Ch 1 is vertical and 2 is horizontal and vice
versa on neighbouring satellites).
• The 15.7 kHz horizontal sweep signal produced by a TV can be heard by some young
people. This common contaminant signal to VLF spectra listening is depicted as
.
Radio Bands
Visible Spectrum
• The range of EMR visible to humans is also 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 have a different response to colours than do humans.
• The sky is blue because our atmosphere scatters light and the shorter
wavelength blue gets scattered the most. It appears that the entire
sky is illuminated by a blue light but in fact that light is scattered from
the sun. The longer wavelengths like red and orange move straight
through the atmosphere which makes the sun look like a bright white
ball containing all the colours of the visible spectrum.
• Interestingly, the visible spectrum covers approximately one octave.
• Astronomers use filters to capture specific wavelengths and reject
unwanted wavelengths, the major astronomical (visual) filter bands
are depicted as X
Infrared Radiation
• The radio spectrum (ELF to EHF) is populated by many more items than can be
shown on this chart, only a small sampling of bands used around the world have
been shown.
• Infrared radiation (IR) is sensed by humans as heat and is below the
range of human vision. Humans (and anything at room temperature)
are emitters of IR.
• Communication using EMR is done using either:
• IR remote control signals are invisible to the human eye but can be
detected by most camcorders.
– Amplitude Modulation (AM)
• Night vision scopes/goggles use a special camera that senses IR and
converts the image to visible light. Some IR cameras employ an IR
lamp to help illuminate the view.
OR
– Frequency Modulation (FM)
• IR LASERs are used for burning objects.
• Each country has its own rules and regulations for allotting bands in this region.
For more information, look up the radio communications authority in your area (Ex.
FCC in the US, DOC in Canada).
• A demonstration of IR is to hold a metal bowl in front of your face.
The IR emitted by your body will be reflected back using the parabolic
shape of the bowl and you will feel the heat.
• Not all references agree on the ULF band range, the HAARP range is used here.
• Fiber-optic based infrared communication signals are sometimes amplified with Erbium-Doped Fiber Amplifiers EDFA
• RAdio Detecting And Ranging (RADAR) uses EMR in the microwave range to detect
the distance and speed of objects.
• Citizens Band Radio (CB) contains 40 stations between 26.965-27.405MHz.
• Schumann resonance is produced in the cavity between the Earth and the ionosphere.
The resonant peaks are depicted as S
• Hydrogen gas emits radio band EMR at 21cm H
• Some individual frequencies are represented as icons:
xxHz
LASER
• LASER is an acronym for Light Amplification by Stimulated Emission
of Radiation.
• A LASER is a device that produces monochromatic EMR of high
intensity.
Submarine communications
• With proper equipment, any EMR can be made to operate like a
LASER. For example, microwaves are used to create a MASER.
Time and frequency standards
xxm Ham radio and international meter bands
Miscellaneous short wave radio
W Weather stations
CP Cellular and PCS Phones (including; FDMA, TDMA, CDMA ranges)
Sound
Polarization
• As a photon (light particle) travels through space, its axis of electrical
and magnetic fluctuations does not rotate. Therefore, each photon
has a fixed linear polarity of somewhere between 0◦ to 360◦ . Light
can also be circularly and elliptically polarized.
• Some crystals can cause the photon to rotate its polarization.
• 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 sound waves.
• Receivers that expect polarized photons will not accept photons that
are in other polarities. (ex. satellite dish receivers have horizontal
and vertical polarity positions).
• Sound waves are caused by an oscillating compression of molecules.
Sound cannot travel in a vacuum such as outer space.
• A polarized filter (like PolaroidTM sunglasses) can be used to demonstrate polarized light. One filter will only let photons that have one
polarity through. Two overlapping filters at right angles will almost
totally block the light that exits, however, a third filter inserted between the first two at a 45◦ angle will rotate the polarized light and
allow some light to come out the end of all three filters.
• The speed of sound in air is 1240kph (770mph).
• Humans can only hear sound between ≈20Hz to ≈20kHz.
• Infrasound (below 20Hz) can be sensed by internal organs and touch.
Frequencies in the 0.2Hz range are often the cause of motion sickness.
• Bats can hear sound up to ≈50kHz.
• The 88 piano keys of the Equal Temperament scale are accurately
located on the frequency chart.
• Over the ages people have striven to divide the continuous audio frequency spectrum into individual musical notes that have harmonious
relationships. Microtonal musicians study various scales. One recent
count lists 4700 different musical scales.
• Perhaps the most reliably polarized light is a rainbow.
• Moonlight is also slightly polarized. You can test this by viewing the
moonlight through a PolaroidTM sunglass lens, then rotate that lens,
the moonlight will dim and brighten slightly.
Refraction
• Middle C is depicted on the chart as C
Sp
• Light that reflects off an electrical insulator becomes polarized. Conductive reflectors do not polarize light.
• Refraction of EMR is dependent on wavelength as can be seen by the
prism example below.
eak
er
This image depicts air
being compressed as
sound waves in a tube
from a speaker and
then travelling through
the tube towards the
ear.
By using a glass prism, white light
can be spread by refraction into a
spectrum of its composite colours.
All wavelengths of EMR can be refracted by using the proper materials.
r
Ea
Source
Convex lenses make objects appear closer and are used to correct
far-sitedness.
Source
Concave lenses make objects appear farther away and are used to
correct near-sitedness.
Focal point
Gravity Waves
• Gravity is the mysterious force that holds large objects together and
binds our planets, stars and galaxies together. Many people have unsuccessfully theorized about the details of gravity and its relationship
to other forces. There have been no links between gravity waves and
electromagnetic radiation.
• Gravity is theorized to warp space and time. In fact, gravity is responsible for bending light as observed by the gravity-lens example of
distant galaxies.
• “Gravity waves” would appear as ripples in space-time formed by large
objects moving through space that might possibly be detected in the
future by very sensitive instruments.
• The speed that gravity propagates through space has been theorized
to be the same as the speed of light.
Heartbeats
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 science is not as exact 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.
Photo by STScI
2.25 PHz
62.8 nm
485 PHz
Power
4.50 PHz
31.4 nm
694 pm
1.89 keV
5.55 nm
51.0 PHz
199 eV
111
FUV
9.01 PHz
347 pm
2.25 keV
+E
• There is no limit to either end of this chart, however, due to limited space, only the
“known” items have been shown here. A frequency of 0Hz is the lowest possible
frequency but the method of depicting octaves used here does not allow for ever
reaching 0Hz, only approaching it. Also, by the definition of frequency (Cycles per
second), there is no such thing as negative frequency.
1.15 EHz
60.6 PHz
13.2 nm
21.4 PHz
83.6 eV
4.50 keV
237 eV
6.60 nm
42.8 PHz
167 eV
292 pm
• The horizontal bars wrap around from far right to far left as the frequency increases
upwards.
969 PHz
2.78 nm
102 PHz
398 eV
3.30 nm
85.7 PHz
335 eV
146 pm
3.78 keV
Soft XRay
110
400
Virus 17300nm
200nm
100nm
VUV
EUV
ULTRAVIOLET
18.0 PHz
15.7 nm
1.94 EHz
7.57 keV
T=2.725K
36.0 PHz
7.85 nm
204 PHz
796 eV
1.65 nm
109
10nm
72.1 PHz
3.93 nm
408 PHz
1.59 keV
826 pm
171 PHz
669 eV
1.96 nm
815 PHz
3.18 keV
413 pm
9.00 keV
2.31 EHz
• Frequency increases on the vertical scale in the upward direction.
Hard XRay
343 PHz
1.34 keV
1.63 EHz
6.36 keV
18.0 keV
• 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.
0 MJy/sr
144 PHz
1nm
982 pm
174 pm
73.0 pm
How to read this chart
Intensity
288 PHz
3.26 EHz
3.88 EHz
15.1 keV
• EMR is emitted in discrete units called photons but has properties
of waves as seen by the images below. EMR can be created by the
oscillation or acceleration of electrical charge or magnetic field. EMR
travels through space at the speed of light (2.997 924 58 ×10 8 m/s).
EMR consists of an oscillating electrical and magnetic field which are
at right angles to eachother and spaced at a particular wavelength.
There is some controversy about the phase relationship between the
electrical and magnetic fields of EMR, one of the theoretical representations is shown here:
B
+
X-RAYS
Xray
machines
86.8 pm
4.61 EHz
Electromagnetic Radiation (EMR)
-B
576 PHz
Gamma Ray
206 pm
686 PHz
2.68 keV
491 pm
2.74 EHz
0.1nm
12.7 keV
103 pm
1.37 EHz
5.35 keV
245 pm
51.6 pm
36.0 keV
Ultrasonic
1.15 EHz
Water
Molecule
0.3nm
10.7 keV
123 pm
5.48 EHz
36.5 pm
Human Audible range
2.31 EHz
21.4 keV
61.4 pm
Ionizing radiation : Harmful to living tissue.
4.61 EHz
6.52 EHz
25.5 keV
30.3 keV
9.22 EHz
Subsonic - Infrasound
GAMMA RAYS
Radioactive
elements
43.4 pm
∞Hz
1
m
∞
∞eV
7.76 EHz
400 MJy/sr
Sizes of
EMR
101
Sources
of EMR
Reflection
• Reflection of EMR is dependent on wavelength as demonstrated when
visible light and radio waves bounce off objects that X-Rays would
pass through. Microwaves, which have a large wavelength compared
to visible light, will bounce off metal mesh in a microwave oven
whereas visible light will pass through.
Source
Ocean Waves
c
%
unihedron.com
2004-10-24
Heavy objects like dense galaxies
and large planets cause light to
bend due to gravitational lensing.
θr
EMR of any wavelength can be reflected, however, the reflectivity of
a material depends on many factors including the wavelength of
the incident beam.
Reflector
The angle of incidence (θi ) and
angle of reflection (θr ) are the
same.
θi