what equation did Einstein make about conservation of energy in photons?
hf = work function + maximum kinetic energy
the energy of each individual photon must be conserved because all its energy is transferred to the photoelectron
why do some electrons require more energy than others?
electrons are different distances away from the surface of the metal and some are closer to the positive ions than others
an electron which requires the minimum energy to free it would have the maximum kinetic energy
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what equation did Einstein make about conservation of energy in photons?
hf = work function + maximum kinetic energy
the energy of each individual photon must be conserved because all its energy is transferred to the photoelectron
why do some electrons require more energy than others?
electrons are different distances away from the surface of the metal and some are closer to the positive ions than others
an electron which requires the minimum energy to free it would have the maximum kinetic energy
what does the graph of kinetic energy vs incident frequency?
kinetic energy= hf - work function
the y intercept is the negative work function
the gradient is planck’s constant
what is wave-particle duality?
the idea that subatomic particles have wavelengths and can be made to exhibit wave properties like diffraction
also electromagnetic radiation can be described as waves (just normal waves) or particles (photons)
normally applied to electrons, but also works for neutrons and protons too (they’re just harder to observe due to their large mass/ large momentum, small wavelength)
what is electron diffraction?
if an electron gun fires electrons at a thin piece of polycrystalline graphite, the electrons pass between the individual carbon atoms
the gap between the atoms is similar in size to the wavelength of the electrons
so the electrons form a diffraction pattern
the electrons behave as particles when they are accelerated by the high p.d, then as waves when they diffract, then as particles when they hit the screen with discrete impacts
what is the de broglie equation?
wavelength = h / momentum
therefore wavelength is inversely proportional to the momentum as planck’s constant is a constant lol
what’s another equation?
wavelength= h / square root of (2*kinetic energy*mass)
derived from kinetic energy equation and momentum