13. quantum physics

Question 1

what is the photoelectric effect

Answer 1

photon of sufficient energy interacts with the surface of a metal and releases a photoelectron

Question 2

what is Plank’s constant

Answer 2

h = 6.63x10^-34

Question 3

what are the equations involving energy and plank’s constant

Answer 3

E=hf

E=hc/λ

Question 4

what is a photon

Answer 4

a packet/ particle of electromagnetic radiation

Question 5

what is the elementary charge

Answer 5

electric charge carried by a single proton(+) or electron (-)

1.6x10^-19

Question 6

how is the photoelectric effect proof of the particulate behaviour of light/ em radiation?

Answer 6

the emission of the photoelectron happens almost instantly. this proves particulate theory, as wave nature suggests that emissions take time

Question 7

what is the symbol used for work function?

Answer 7

Φ (phi)

Question 8

what is the work function Φ?

Answer 8

the minimum amount of energy required in a photon to release an electron from the surface of the metal

Question 9

what’s the symbol for threshhold frequency?

Answer 9

f₀

Question 10

what is threshhold frequency f₀?

Answer 10

the minimum photon frequency required to release an electron from the surface of a metal

Question 11

how does the intensity of the light effect the energy of electrons

Answer 11

while there are more emitted per unit time, the energy (Ekmax) is unchanged

(intensity of light is independant from photon emission, as if the frequency of the light is below the threshold frequency (f₀) then photon energy is below the material’s work function and no electrons can be released)

Question 12

how can an electron be raised to a higher energy level

Answer 12

1. absorb a photon
2. absorb energy from a free electron colliding with it.

Question 13

what happens when a photon de-excites

Answer 13

it emits a photon of energy equal to the drop in energy