DP Physics (last assessment 2024)
Question 19M.3.HL.TZ1.20a
| Date | May 2019 | Marks available | [Maximum mark: 2] | Reference code | 19M.3.HL.TZ1.20a |
| Level | HL | Paper | 3 | Time zone | TZ1 |
| Command term | Explain | Question number | a | Adapted from | N/A |
a.
[Maximum mark: 2]
19M.3.HL.TZ1.20a
(a)
Light from distant galaxies is redshifted. Explain the cosmological origin of this redshift.
[2]
Markscheme
«according to general relativity» space expands stretching distances between far away objects ✔
wavelengths of photons «received a long time after they were emitted» are thus longer leading to the observed redshift ✔
Do not accept references to the Doppler effect.
Examiners report
Cosmological origin of redshift. The cosmological redshift and variation with time of the cosmic scale factor proved to be a well-mastered concept by many students.
