Wave Particle Duality Flashcards
What conditions are there for photoelectric emission to take place?
Photoelectric emission takes place when ultraviolet radiation is shone on to a negatively charged zinc plate. This causes electrons to be ejected from the plate until it is discharged.
The photoelectric effect can be demonstrated using?
A gold leaf electroscope?
Function of gold leaf electroscope?
can be used to measure small amounts of positive or negative charge
What happens when a gold leaf electroscope is charged
gold leaf will be repelled from its support
How to discharge a charged electroscope and why?
By bringing a burning taper near to the cap. This is because the flame ionises the air around it.
If the electroscope is positively charged the negative ions will be attracted towards it and so cause it to discharge.
If the electroscope is negatively charged the positive ions will attracted towards it and cause the electroscope to discharge.
How else could you discharge a negatively charged electroscope?
light shining on the cap of an electroscope if the light source has a high enough frequency which is usually in the UV range
How can the photoelectric effect explain wave particle duality?
Light behaves like a particle and that the energy of the particle, (photon), is related to the frequency of the radiation.
The energy of a photon of visible light is not enough to produce the photoelectric effect in either steel or zinc.
What does increasing irradiance of a source do?
Increases the number of photons arriving at the surface per second. As there are more photons hitting the metal per second, more electrons will be removed per second.
If photons do not have enough energy to cause a removal of an electron, what does increasing the irradiance do?
Increasing the irradiance will make no difference as electrons will still not be removed.
What is threshold frequency?
minimum frequency for which photoemission will occur for any particular substance
What is work function?
minimum energy of a photon required to cause photoemission.
Work function?
wf=hf0
