Energy and momentum of a photon: past paper questions

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• Question 8May/June 2026, paper 41Structured13 marks

  State what is meant by a photon.

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• Question 8Oct/Nov 2023, paper 41Structured10 marksHas a diagram

  Show that the momentum $p$ of a photon of electromagnetic radiation with wavelength $\lambda$ is given by $$p=\frac{h}{\lambda }$$ where $h$ is the Planck constant.

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• Question 9May/June 2026, paper 42Structured10 marks

  State what is meant by the de Broglie wavelength.

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• Question 8Oct/Nov 2025, paper 42Structured10 marksHas a diagram

  Fig. 8.1 shows the three lowest-frequency lines in the part of the emission spectrum for hydrogen that relates to electron transitions to the ground state (level $n=1$).

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• Question 8May/June 2024, paper 42Structured12 marksHas a diagram

  Fig. 8.1 shows part of the emission spectrum of visible radiation emitted by hydrogen gas in a star in a distant galaxy. The galaxy is moving away from the Earth at a speed of $6.2\times {10}^6{\text{ m s}}^{-1}$.

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• Question 8May/June 2023, paper 42Structured8 marksHas a diagram

  Fig. 8.1 shows the lowest four energy levels of an electron in an isolated atom. Fig. 8.2 shows the lines in the emission spectrum of the atom that correspond to the transitions of the electron from $n=3$ to $n=1$ and from $n=4$ to $n=1$.

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