25.3 Hubble’s law and the Big Bang theory

understand that the lines in the emission and absorption spectra from distant objects show an increase in wavelength from their known values.

Use —the lines in the emission and absorption spectra to connect the rule to the data and decision in the question.

This matters because —the lines in the emission and absorption spectra determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply —the lines in the emission and absorption spectra to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: —The lines in the emission and absorption spectra is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.

use ∆λ / λ ≈ ∆f / f ≈ v / c for the redshift of electromagnetic radiation from a source moving relative to an observer.

Use —redshift of electromagnetic radiation to connect the rule to the data and decision in the question.

This matters because —redshift of electromagnetic radiation determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply —redshift of electromagnetic radiation to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: —Redshift of electromagnetic radiation is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.

explain why redshift leads to the idea that the universe is expanding.

Use —why redshift leads to the idea that the universe is expanding to connect the rule to the data and decision in the question.

This matters because —why redshift leads to the idea that the universe is expanding determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply —why redshift leads to the idea that the universe is expanding to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: —Why redshift leads to the idea that the universe is expanding is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.

recall and use Hubble’s law v ≈ H0d and explain how this leads to the Big Bang theory (candidates will only be required to use SI units).

Use —hubble’s law v ≈ h0d and explain how this leads to the big bang theory to connect the rule to the data and decision in the question.

This matters because —hubble’s law v ≈ h0d and explain how this leads to the big bang theory determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply —hubble’s law v ≈ h0d and explain how this leads to the big bang theory to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: —Hubble’s law v ≈ H0d and explain how this leads to the Big Bang theory is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.