1. Continuous Spectra
·
all i possible wavelengths.
Hot
things a
emit continuous
spectrum in the
visible and infrared.
All the allowedbecause were
wavelengths are
ined they bound atoms, free
to
energy levels, not to
a re
-
I are
lost photons
Emission
excited
gas originally), de-excites, emitting photons
2.
Spectra
~
lightfrom flouresenttubes
through a
prism or a diffraction
grating
each line
corresponds to a
particular wavelength.
·since
only certain
photon energies are allowed, only corresponding
is to
those seen
energies are
3.
Absorption Spectrum Smine e
Ide-excite)
White
lightthrough cool gas.
·
Why cool
gas?
At low to, of the e in the are in state.
most
gas ground
-
These absorb
photons specific wavelengths from the white
lightand getexcited.
-
I of
-
These I then from continuous
a re
missing spectrum.
lool from the continuous
certain
spectrum.
·
removes
gas
Black the absorbed
lines
correspond to
wavelengths.
·
light
he rate set
photons
, ne FluorescentTube an e
liberation of e from heated materials
Ms.The cathode is heated
causing
peturns intovisit
the
themionic emission. This causes free e to be
released from the surface.
2.The I are accelerated
by a potential difference.
They
then collide with electrons
mercury atoms, causing
in
them levels.
emitted
by atoms
to excite to
higher energy
3.When the excited electrons return to the
ground
4.A
state,
they emit
photons in the UV
range.
absorbs these
phosphor coating photos,
electron has
n atom in which an
higher energy
than the
groundstate. exciting its electrons to
higher orbits.
5. These electrons then cascade down the
Electrons are accelerated
by the
high voltage and
levels, emitting photons of in the form
collide with electrons in
mercury atoms,
causing
them to
energy many
excite
of visible
light.
The
e.
phosper atoms of the
coating
absorb
photons. Theybecome
excited of different form
andemit photons wavelengths in the
of visible
light