DP Physics (last assessment 2024)
Question 20N.3.HL.TZ0.b
| Date | November 2020 | Marks available | [Maximum mark: 2] | Reference code | 20N.3.HL.TZ0.b |
| Level | HL | Paper | 3 | Time zone | TZ0 |
| Command term | Outline | Question number | b | Adapted from | N/A |
b.
[Maximum mark: 2]
20N.3.HL.TZ0.b
Outline how a gradient field allows NMR to be used in medical resonance imaging.
[2]
Markscheme
mention of gradient field «added to the NMR uniform magnetic field» ✓
reference to «the total field that determines» the output «Larmor» frequency from the de-excitation ✓
different positions «in the body» give rise to different frequencies ✓
«and this can be mapped»
Examiners report
Most candidates continued successfully here by referring to a gradient field eventually leading to a mapping of the position of the protons from (a).
