| Date | November 2010 | Marks available | 1 | Reference code | 10N.3.SL.TZ0.E2 |
| Level | Standard level | Paper | Paper 3 | Time zone | Time zone 0 |
| Command term | Describe | Question number | E2 | Adapted from | N/A |
Question
This question is about the Big Bang model and red-shift.
In the 1960s, Penzias and Wilson discovered a uniform cosmic background radiation (CMB) in the microwave region of the electromagnetic spectrum.
Describe what is meant by the Big Bang model.
(i) Explain how the CMB is consistent with the Big Bang model.
(ii) State why the red-shift of light from galaxies supports the Big Bang model.
Markscheme
space and time originated from a single point in a large explosion / an expanding universe that originated from a single point / OWTTE;
(i) temperature of the universe immediately after the Big Bang was very high;
as it expanded it cooled down;
the wavelength of the CMB corresponds to a temperature consistent with this cooling down / OWTTE;
red shift is due to expansion of universe;
(ii) indicates that the universe is expanding;
Examiners report
Many candidates knew what is meant by the Big Bang Model.
An understanding of CMB in and its relevance to the Big Bang Model was only demonstrated by a minority of candidates. In (b) (ii) it was not sufficient to say that galaxies are moving away from Earth; a statement to the effect that the universe is expanding was required.
