Unit 2: atoms and light Flashcards
electrons are what…
particles and behave like magnets
how can you get more photons
higher intensity
wavelength, frequency units
nm or m
s-1 or hz
light is more intense if…
bright and has greater amplitude
what does shorter wavelengths result to
higher frequency, greater threshold, and more electrons emitted
light has
wave and particle-like properties
the “particles” are called
photons, which are packets of energy
are electrons emitted as long as there is a high frequency?
no, depends on threshold frequency. if lower than the threshold frequency, no electrons are emitted
energy is related to…
light of photon
some energy is used to
overcome forces that bind the electron to the metal, and the remaining energy shows up as kinetic energy of the ejected electron
in one light source do all photons in that light source have the same amount of energy?
yes
in formula KE(electron)= hv-hvo
what does it stand for?
hvo= threashold frequency (enegy of metal- each metal has a different value)
hv= energy per 1 photon aka energy of light
if hv not given, how can we find that
E(photon)=hv
or, if v not given and wavelength is, we use E=hc/wavelength
calculating frequency of 1 photon? vs calculating frequency of the light
frequency corresponds to energy of photon so E(photon)=hv
or, if v not given and wavelength is, we use E=hc/wavelength
frequency of the light: use c=wavelength x frequency (v)
no electrons ejected if
hv<hvo
true of false: one photon removes 2 electrons
FALSE.
ONCE ON ONE
when a metal surface absorbs a photon, the energy of the photon is…
transferred to an electron
what do you need to calculate kenitic energy of an electron
hvo and hv,
if no hv, you use it with energy of photon formula
(either the one with frequency or with wavelength)
When light interacts with a relatively large body (prism) its
wave properties dominate the interaction.
When light interacts with small body (atom, electron)
particle
properties dominate the interaction.
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