quantum

Question 1

what did the photoelectric effect prove

Answer 1

light has particle like behaviours

Question 2

what are EM waves released as

Answer 2

discrete packets called quanta

Question 3

relationship between energy and frequency

Answer 3

the hgiher the frequency, the higher the energy

Question 4

what are photon energies measured in

Answer 4

electronvolts

Question 5

electronvolt defintion

Answer 5

the kinetic energy gained by an electron when it is accelerated through a potential difference of 1 volt

Question 6

what happens in the photoelectric effect

Answer 6

free electrons on the surface of the metal absorb energy from the light
if an electron absorbs enough energy, the bonds holding it to the metal break and it is emitted from the surface

Question 7

gold leaf electroscope explanation

Answer 7

-electroscope is initially negatively charged, so the gold leaf is repelled
-the zinc plate is then exposed to ultraviolet light and the photoelectric effect acuses its free electrons to be ejected. this causes it to lose its negative charge-the gold leaf is no longer repelled so it drops down

Question 8

three conclusions drawn from the golden leaf electroscope experiment

Answer 8

1- for a given metal no photoelectrons are emitted if the radiation has a frequency below a certain value, this frequency is the threshold frequency
2- the photoelectrons are emitted with a variety of kinetic energies ranging from zero to some maxiomum value. the value of this maximum kinetic energy increases with the frequency of the radiation, and is uneffected by the intensity of the equation
3- the number of photoelectrons emmited per second is proportional to the intensity of the radiation

Question 9

work function definition

Answer 9

the minimum energy required to release a photoelectron from the surface of a metal