| Date | May 2013 | Marks available | 2 | Reference code | 13M.3.SL.TZ1.12 |
| Level | Standard level | Paper | Paper 3 | Time zone | Time zone 1 |
| Command term | Describe | Question number | 12 | Adapted from | N/A |
Question
This question is about the Ω– particle.
The Ω– particle is a baryon which contains only strange quarks.
This question is about laser light.
Deduce the strangeness of the Ω– particle.
The Feynman diagram shows a quark change that gives rise to a possible decay of the Ω– particle.
(i) Identify X.
(ii) Identify Y.
The number of lines per millimetre in the diffraction grating in (b) is reduced. Describe the effects of this change on the fringe pattern in (b).
Markscheme
-3;
(i) anti u (quark) /\(\bar u\);
(ii) W–;
principal maxima broaden;
secondary maxima appear;
Examiners report
Many candidates knew about the idea of strangeness, but did not assign a numerical value.
Was reasonably well answered.
There were almost no correct answers. Candidates clearly need a lot of practice answering questions on the diffraction grating.
