Question 21M.2.HL.TZ2.9
| Date | May 2021 | Marks available | [Maximum mark: 6] | Reference code | 21M.2.HL.TZ2.9 |
| Level | HL | Paper | 2 | Time zone | TZ2 |
| Command term | Calculate, Explain, Outline | Question number | 9 | Adapted from | N/A |
In an experiment to demonstrate the photoelectric effect, monochromatic electromagnetic radiation from source A is incident on the surfaces of metal P and metal Q. Observations of the emission of electrons from P and Q are made.
The experiment is then repeated with two other sources of electromagnetic radiation: B and C. The table gives the results for the experiment and the wavelengths of the radiation sources.
Outline the cause of the electron emission for radiation A.
[1]
photon transfers «all» energy to electron ✓
Outline why electrons are never emitted for radiation C.
[1]
photon energy is less than both work functions
OR
photon energy is insufficient «to remove an electron» ✓
Answer must be in terms of photon energy.
Outline why radiation B gives different results.
[1]
Identifies P work function lower than Q work function ✓
Explain why there is no effect on the table of results when the intensity of source B is doubled.
[1]
changing/doubling intensity «changes/doubles number of photons arriving but» does not change energy of photon ✓
Photons with energy 1.1 × 10−18 J are incident on a third metal surface. The maximum energy of electrons emitted from the surface of the metal is 5.1 × 10−19 J.
Calculate, in eV, the work function of the metal.
[2]
✓
work function ✓
Award [2] marks for a bald correct answer.
