quantum is boring

Question 1

EM radiation is shone on a zinc plate; low intensity UV caused electron emission; high intensity visible light did nothing; explain these observations

Answer 1

photons have 1 to 1 interactions with electrons; energy of UV photons is above zinc’s work function so electrons are emitted; photon energy depends on frequency, not intensity ( E = hf )

Question 2

what is a photon

Answer 2

a packet of EM energy

Question 3

what effect does light intensity have on the photoelectric effect

Answer 3

more photons per second => higher rate of electron emission (directly proportional)

Question 4

what effect does light colour have on the photoelectric effect

Answer 4

higher freq light => higher energy photons => higher max KE electrons emitted

Question 5

describe a piece of evidence for electrons behaving like waves

Answer 5

they diffract when fired through graphene

Question 6

explain why electron energy levels are written as negative

Answer 6

electrons need to gain energy to leave the atom

Question 7

state how an emission line is produced in a spectrum

Answer 7

electron moves to a lower energy level; energy released as a photon