1.
State what is meant by the standard model.
[1 mark]
- quarks, leptons, exchange bosons
JD SCIENCE
Module 6 Particles and medical physics
Indicative marking points. Award marks for equivalent scientific or mathematical wording. Do not issue this sheet with the student worksheet.
2.
State what is meant by a hadron.
[1 mark]
- made of quarks, feels the strong force
3.
State what is meant by the photoelectric effect.
[1 mark]
- electrons emitted if f > f₀
4.
State what is meant by wave-particle duality.
[1 mark]
- electrons show diffraction
5.
State what is meant by annihilation.
[1 mark]
- particle + antiparticle → photons
6.
State what is meant by pair production.
[1 mark]
- a photon → particle + antiparticle
7.
State what is meant by the electronvolt.
[1 mark]
- 1.6 × 10⁻¹⁹ J
8.
State what is meant by a Feynman diagram.
[1 mark]
- shows exchange particles
9.
State what is meant by beta-minus decay.
[1 mark]
- neutron → proton + e⁻ + antineutrino
10.
State what is meant by specific charge.
[1 mark]
- charge/mass
11.
Grace is asked about the standard model in a OCR Physics paper.
(a) [2 marks]
- up down strange; electron, neutrino
(b) [3 marks]
- charge must be conserved
12.
Grace is asked about a hadron in a OCR Physics paper.
(a) [2 marks]
- baryons 3 quarks, mesons quark+antiquark
(b) [3 marks]
- proton is uud
13.
Grace is asked about the photoelectric effect in a OCR Physics paper.
(a) [2 marks]
- hf = φ + Ek max
(b) [3 marks]
- evidence for photons
14.
Grace is asked about wave-particle duality in a OCR Physics paper.
(a) [2 marks]
- de Broglie λ = h/p
(b) [3 marks]
- particles have wave nature
15.
Grace is asked about annihilation in a OCR Physics paper.
(a) [2 marks]
- energy 2mc² minimum
(b) [3 marks]
- PET scanners
16.
Grace is asked about pair production in a OCR Physics paper.
(a) [2 marks]
- near a nucleus
(b) [3 marks]
- hf ≥ 2mc²
17.
E = hf. f=5.0×10¹⁴, h=6.63×10⁻³⁴
[3 marks]
- Final answer: 3.32 × 10⁻¹⁹ J
18.
φ = 2.0 eV. f₀ = φ/h
[3 marks]
- Final answer: 4.8 × 10¹⁴ Hz
19.
λ = h/mv. m=9.1×10⁻³¹, v=2.0×10⁶
[3 marks]
- Final answer: 0.36 nm order
20.
2mc² for electron (0.511 MeV)
[3 marks]
- Final answer: 1.022 MeV
21.
Quark composition of a neutron
[3 marks]
- Final answer: udd
22.
Charge of a uud proton in e
[3 marks]
- Final answer: +1
23.
Grace carries out a OCR-style required practical linked to particles and radiation. This is a typical OCR required-practical style question.
(a) [2 marks]
- Independent: the independent variable for this topic
- Dependent: the measured outcome
(b) [2 marks]
- keep all other variables constant
- so the test is fair / only one variable is changed
(c) [2 marks]
- repeat and calculate a mean / use a tighter method
24.
Grace carries out collecting valid data for particles and radiation. This is a typical OCR required-practical style question.
(a) [2 marks]
- Independent: a chosen factor
- Dependent: a quantitative measurement
(b) [2 marks]
- calibrated instrument
- so the test is fair / only one variable is changed
(c) [2 marks]
- systematic error from zero error
25.
Grace carries out drawing a graph for particles and radiation. This is a typical OCR required-practical style question.
(a) [2 marks]
- Independent: x-variable
- Dependent: y-variable
(b) [2 marks]
- same scale / same apparatus
- so the test is fair / only one variable is changed
(c) [2 marks]
- not drawing a line of best fit through the trend
26.
Grace carries out evaluating a method about particles and radiation. This is a typical OCR required-practical style question.
(a) [2 marks]
- Independent: method change
- Dependent: precision / accuracy
(b) [2 marks]
- same sample size
- so the test is fair / only one variable is changed
(c) [2 marks]
- too few repeats
27.
Compare the standard model with a hadron.
[4 marks]
- quarks, leptons, exchange bosons
- made of quarks, feels the strong force
- give one linked difference
28.
Compare a hadron with the photoelectric effect.
[4 marks]
- made of quarks, feels the strong force
- electrons emitted if f > f₀
- give one linked difference
29.
Compare the photoelectric effect with wave-particle duality.
[4 marks]
- electrons emitted if f > f₀
- electrons show diffraction
- give one linked difference
30.
Compare wave-particle duality with annihilation.
[4 marks]
- electrons show diffraction
- particle + antiparticle → photons
- give one linked difference
31.
Apply your knowledge of the electronvolt to this situation: convenient energy unit
[3 marks]
- convenient energy unit
32.
Apply your knowledge of a Feynman diagram to this situation: EM: virtual photon; weak: W±
[3 marks]
- EM: virtual photon; weak: W±