| Date | May 2016 | Marks available | 3 | Reference code | 16M.3.HL.TZ0.20 |
| Level | Higher level | Paper | Paper 3 | Time zone | Time zone 0 |
| Command term | Describe | Question number | 20 | Adapted from | N/A |
Question
State the Jeans criterion for star formation.
[2]
a.
Describe three differences between type Ia and type II supernovae.
[3]
b.
Markscheme
a gas cloud will collapse to form a star
if «the magnitude of» the gravitational potential energy of the particles is greater than the kinetic energy of the particles OR mass of the cloud is greater than the Jeans mass
a.
Ia have consistent maxima in their light curves but II vary
Ia has a strong ionized SiII line but II has hydrogen lines in their spectra
Ia was a white dwarf but II are massive stars
Ia form from binary systems but II are the result of core collapse of a star
Ia can be used as standard candles but II are not
b.
Examiners report
[N/A]
a.
[N/A]
b.
