DP Physics (last assessment 2024)
Question 19N.3.HL.TZ0.b(iii)
| Date | November 2019 | Marks available | [Maximum mark: 2] | Reference code | 19N.3.HL.TZ0.b(iii) |
| Level | HL | Paper | 3 | Time zone | TZ0 |
| Command term | Discuss | Question number | b(iii) | Adapted from | N/A |
b(iii).
[Maximum mark: 2]
19N.3.HL.TZ0.b(iii)
Evidence from the Planck space observatory suggests that the density of matter in the universe is about 32 % of the critical density of the universe.
It is estimated that less than 20 % of the matter in the universe is observable. Discuss how scientists use galactic rotation curves to explain this.
[2]
Markscheme
rotation speed of galaxies is larger than expected away from the centre ✔
there must be more mass «at the edges» than is visually observable «indicating the presence of dark matter» ✔
