Electromagnetic Radiation

P1B summary of Electromagnetic Radiation

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  • Created on: 27-06-11 16:39
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Electromagnetic Radiation
El
ectr
oma gneti
c radi
ati
on t
ravels
as waves.
(Radi
ati
on
li
ter
all
y means
that
i
t
tr
avels
out
r
adial
ly
ie
fr
om t
he radi
us.
We can
see t
his
eff
ect
w i
th
visi
ble
li
ght
i
f
w e
have
a candl
e i
n a
dar
k r
oo m,
it
pr
o duces
w hat
seems
to
be a
ball
of
l
ight
around
the
fl
ame ,
and
thi
s means
that
t
he vi
si
b l
e l
i
g ht
i
s coming
ou t
f
rom the
candle
in
all
di
rect
ions.
)
Al
l
w aves
are
produced
by
vibr
ati
ons.
Waves
tr
ansf
er
ener
gy
fr
om
one
place
to
anot
her
.
El
ectr
oma gnet
ic
(EM)
w aves
a r
e speci
al
because
they ar
e
produced when
atoms vi
brat
e i
n
el
ect
ri
c and
ma gnet
ic
fi
elds.
(
T he
numb er
of
ti
mes t
h e
atoms
vibr
ates
each
second i
t
call
ed
t
he f
requency.
The
fr
equen cy
of
the
vibr
ati
ons t
ell
s us
w hat
t
ype
of
EM wave i
s pr
oduced).
Al
l
E M
w aves
can t
ravel
t
hrough
a vacuum (a
place
w her
e t
her
e i
s no
part
icl
es
a t
al
l)
.
These
waves
tr
avel
abo ut
t
he
same
speed
in
air
as
they
do i
n a
vacuum.
This
speed i
s t
he same
for
8
al
l
EM waves ­ 300
000 000
m/s or
3x10 m/s.
Because
atoms
can
vibr
ate
at
any
fr
equency,
t
hey
can
produce
w aves
of
any
fr
equency.
Waves
have
four
basi
c c
h ar
act
eri
sti
cs:
The frequency ­
ho w many complet
e waves
occur
each second.
A
high
frequency
me ans
l
ots
o f
w aves
each second,
a l
ow f
requency
me ans
few waves
each second.
The
fr
e quency
of
a w ave
is
me asur
ed
in
H er
tz
(Hz)
. 1Her
tz
= 1
w aves
per
second.
The wavelength
­ how l
ong
(i
n met
res)
each
indi
vi
dual
wave
is.
One
w ave
consi
sts
of
one
peak and
one t
rough.
The amplitude ­
thi
s t
ell
s you
how
tal
l
a wave
is
(i
n metr
es).
I
t
is
me asur
ed f
rom the
centr
e
t
o t
h e
top
o f
t
he peak
o r
t
he centr
e t
o t
he
bot
tom of
the
tr
ough.
In
ter
ms
of
w aves,
t
he bi
gger
t
he amp l
it
u de
the
mo r
e
energy i
t
carr
ies.
Vi
si
ble
li
ght
w i
th
a l
arge
amp l
i
tude
w oul
d be a
very
br
ight
li
ght.
The wave speed ­
thi
s t
ell
s us
how fast
each
w ave
tr
avel
s (
in
m/s)
.
All
EM
w aves
tr
avel
at
300 mi
ll
ion m/
s i
n a
vacuum a nd
air
.
The
w ave
speed,
f
requency
and
w avel
engt
h of
a
w ave
are
li
nked
by
the
fol
lowi
ng
equat
ion:
wave
speed = f
requency wavel
engt
h
(
met
re/
second,
m/
s) (
hert
z,
H z) (
me t
re,
m)
Si
nce al
l
EM wave s
tr
avel
at
t
he same
speed t
hen t
he f
requency
a nd
the
w avel
ength of
a
wave
are i
nver
sely
propor
ti
onal
to
each
other
.
(A
w ave
w i
th
a l
arge
w avel
ength has
a small
f
requency
and vi
ce ver
sa,
i
f
a wave
has
a l
arge
fr
equ ency
then
it
has
a small
wavelengt
h.)
Si
nce
the
w aves
can
ha v
e
any
fr
equency
or
any
w avel
engt
h,
the
w aves
cover
a
cont
inuous
r
ange
of
w avel
engths.

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Page 2

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Thi
s cont
inuous
range
of
w avel
engt
hs
for
EM
w aves
is
cal
led
the
elect
romagnet
ic
(
E M)
s
p ect
rum.…read more

Page 3

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Speci
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Visible light
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