| Define the terms proper distance, luminosity distance and angular diameter distance. | [1.5] |
| The main point with definitions is to be precise and specific. There's only half a mark each on offer here, so you aren't being asked for anything sophisticated! | |
| Show that the angular diameter distance dA and the luminosity distance dL are related by dA = dL/(1 + z)2 for an object at redshift z. | [3] |
| This is a bookwork derivation starting from the Robertson-Walker metric (which is on the exam cover, so you don't have to remember it). | |
| Does this result rely on assuming that the universe has a flat geometry? | [0.5] |
| Only half a mark, so "Yes" or "No" might suffice – but in this type of question it is always sensible to put in a few words of justification. |
(2006 Q4.)