Particles and Waves: 4 - The Photoelectric Effect/ Wave Particle Duality Flashcards
What is the photoelectric effect?
The photoelectric effect is evidence for the particle model of light.
What experiment can be used to demonstrate the photoelectric effect?
The electroscope.
Describe the electroscope experiment?
First it is charged negatively causing the gold leaf to be repelled. If the leaf falls when light is incident on the metal, then the lectroscope has lost more charge.
What is the explonation of the electroscope experiment?
The UV light causes electrons to leave the metal, which are known as photoelectrons. The light must be behaving like a particle, these particles are called photons and are little pockets of energy.Each photon of light releases one phortoelectron from the surface if the frequency of the light is high enough.
What can photons of suffecient energy do and what is this called?
Photons of sufficient energy can eject electrons from the surface of materials and this is called photo emission
What is the energy of a photon is proprtional to?
The energy of a photon is proportional to its frequency.
What is the calculation for the energy of a photon?
E=hf
What does the h stand for in the equation E=hf?
Plancks constant
Waht is Plancks constant equal to?
6.63x10-34
What is the definition of work function?
The minnimum energy required to eject an electron from a surface.
What is the freshold frequency?
The minimum frequency of a photon required
for photoemission.
What is the equation for the work function?
Eo = h fo
What does the fo stand for in the work function equation?
The threshold frequency.
If the photon provides greater energy than the work function, in what form is the extra energy given to the electron as?
kinetic energy.
How do you work out the kinetic energy given to an electron if the photon provides more energy than the work function?
Ek = hf - hfo
