Question 23M.3.HL.TZ2.17
| Date | May 2023 | Marks available | [Maximum mark: 7] | Reference code | 23M.3.HL.TZ2.17 |
| Level | HL | Paper | 3 | Time zone | TZ2 |
| Command term | Construct, Explain, Outline, State | Question number | 17 | Adapted from | N/A |
Three stars A, B and C are labelled on the Hertzsprung–Russell (HR) diagram. L☉ is the Luminosity of the sun.
State the main element that is undergoing nuclear fusion in star C.
[1]
Hydrogen ✓
Explain why star B has a greater surface area than star A.
[2]
stars have same/similar L AND star B has lower T ✓
correct reference to luminosity formula (Lα AT4) ✓
MP1 Allow reverse argument i.e., star A has higher T
White dwarfs with similar volumes to each other are shown on the HR diagram.
Construct a line, on the HR diagram, to show the possible positions of other white dwarf stars with similar volumes to those marked on the HR diagram.
[2]
Any evidence of correct identification that three dots bottom left represent white dwarfs ✓
line passing through all 3 white dwarfs OR line continuing from 3 white dwarfs with approximately same gradient, in either direction ✓
Award MP2 if no line drawn through the three dots but just beyond them in either direction
Some stars on the HR diagram are likely to evolve into neutron stars.
Outline why the radius of a neutron star reaches a stable value.
[2]
«inward» gravitational force/pressure ✓
balanced by «neutron» degeneracy pressure/force ✓
Allow force or pressure OWTTE