Wave-Particle Duality

Question 1

what is the photoelectric effect evidence for?

Answer 1

the particle model of light

Question 2

examples of light as a a wave

Answer 2

• refraction
• reflection
• interference

Question 3

example of light as a particle

Answer 3

the photoelectric effect

Question 4

what happens when white light is shone onto a metal plate?

Answer 4

white light photons do not exceed the threshold frequency and therefore the work function

Question 5

what happens when UV light is shone onto a metal plate?

Answer 5

electrons are released as the photons did exceed the threshold frequency

Question 6

relationship which combines energy of a photon and frequency

Answer 6

Ephoton=hf

Question 7

what is the only thing that affects the energy of a photon

Answer 7

the frequency of the photon

Question 8

what does increasing brightness do?

Answer 8

increases the number of photons, not their individual energy

Question 9

what would increasing brightness do if light was a wave?

Answer 9

release an electron

Question 10

Ephoton

Answer 10

no electron are freed

Question 11

Ephoton=Eo

Answer 11

electron freed but does not have sufficient kinetic energy to leave

Question 12

Ephoton>Eo

Answer 12

electron has sufficient kinetic energy to leave

Question 13

formulas to work out kinetic energy

Answer 13

1. Ek=Ephoton-Eo
2. Ek=hf-hfo
3. Ek=1/2mv^2

Question 14

threshold frequency

Answer 14

minimum frequency of a photon required for photoemission.

Question 15

work function

Answer 15

minimum energy of a photon required to cause photoemission.

Question 16

graph of current against frequency

Answer 16

horizontal line across the x-axis until it reaches the threshold frequency. It then curves up with decreasing gradient.