Physics A-Level
red shift
What red shift means in Physics A-Level, as defined for AQA, OCR.
Definitions of red shift
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Reference: AQA
Calculated from observed and rest wavelengths using z = (λ_observed − λ_rest) / λ_rest, and for cosmological red shifts it indicates recession and distance.
A source moving away from the observer has its observed wavelength stretched, producing a red shift.
Topics that use red shift
- Quasars (A-level only) (AQA A-Level)
- Cosmology (OCR A-Level)
Related terms
- Cosmological redshift
- Hubble's law
- Accretion discs and black hole mass
- Active galactic nuclei
- Age of the universe
- Astronomical distance units
- Baseline
- Big Bang nucleosynthesis
Using red shift in the exam
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