User interface language: English | Español

Date May 2011 Marks available 2 Reference code 11M.3.SL.TZ1.15
Level Standard level Paper Paper 3 Time zone Time zone 1
Command term Explain Question number 15 Adapted from N/A

Question

This question is about cosmology.

State how the observed red-shift of many galaxies is explained.

[1]
a.

Explain how the cosmic microwave background (CMB) radiation is consistent with the Big Bang model.

[2]
b.

Calculate the temperature of the universe when the peak wavelength of the CMB was equal to the wavelength of red light (7.0×10−7m).

[2]
c.

Markscheme

the universe is expanding / many galaxies are moving away from us;

a.

the CMBR fills all of space / is uniform / is distributed equally, consistent with an “explosion” (at start of universe);
the temperature of the radiation (2.7 K) is consistent with cooling due to expansion/redshift;

b.

\({\lambda _{\max }} = \frac{{2.9 \times 10 - 3}}{T} \Rightarrow T = \frac{{2.9 \times {{10}^{ - 3}}}}{{7.0 \times {{10}^{ - 7}}}}\);
T = 4100K;

c.

Examiners report

[N/A]
a.
[N/A]
b.
[N/A]
c.

Syllabus sections

Option D: Astrophysics » Option D: Astrophysics (Core topics) » D.3 – Cosmology
Show 58 related questions

View options