Subsection 22.1. Energy and momentum of a photon for Physics, A Level - revisedeck

22.1. Energy and momentum of a photon

A subsection of Physics, 9702, through 22. Quantum physics

Listing 10 of 18 questions

A π0 meson is a sub-atomic particle. A stationary π0 meson, which has mass 2.4 × 10–28 kg, decays to form two γ-ray photons. The nuclear equation for this decay is π0 γ + γ. Explain why the two γ-ray photons have the same energy. Determine, for each γ-ray photon, the energy, in joule, energy = J the wavelength, wavelength = m the momentum. momentum = N s

9702_s10_qp_41

THEORY

2010

Paper 4, Variant 1

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State what is meant by a photon. A stationary cobalt-60 (60 27Co) nucleus emits a γ-ray photon of energy 1.18 MeV. Calculate the wavelength of the photon. wavelength = m Show that the momentum of the photon is 6.3 × 10–22 N s. Use information in to determine the recoil speed of the cobalt-60 nucleus when the γ-ray photon is emitted. speed = m s–1

9702_s19_qp_42

THEORY

2019

Paper 4, Variant 2

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State what is meant by a photon. A stationary nucleus of samarium-157 (157 62 Sm) emits a gamma-ray (γ-ray) photon of energy 0.57 MeV. Determine, for one γ-ray photon: its wavelength wavelength = m its momentum. momentum = N s Using your answer to , determine the speed of the samarium-157 nucleus after emission of the photon. speed = m s−1 By reference to your answer in , explain quantitatively why the speed of the samarium-157 nucleus may be assumed to be negligible compared with the speed of the photon.

9702_s21_qp_42

THEORY

2021

Paper 4, Variant 2

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A stationary isolated nucleus emits a γ-ray photon of energy 0.51MeV. State what is meant by a photon. For the γ-ray photon, calculate its wavelength, wavelength = m its momentum. momentum = N s For this nucleus, determine the change in mass Δm during the decay that gives rise to the energy of the γ-ray photon. Δm = kg Explain why, after the decay, the nucleus is no longer stationary.

9702_w18_qp_41

THEORY

2018

Paper 4, Variant 1

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A stationary isolated nucleus emits a γ-ray photon of energy 0.51MeV. State what is meant by a photon. For the γ-ray photon, calculate its wavelength, wavelength = m its momentum. momentum = N s For this nucleus, determine the change in mass Δm during the decay that gives rise to the energy of the γ-ray photon. Δm = kg Explain why, after the decay, the nucleus is no longer stationary.

9702_w18_qp_43

THEORY

2018

Paper 4, Variant 3

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What is equivalent to 2000 microvolts?

9702_s14_qp_11

MCQ

2014

Paper 1, Variant 1

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Which statement includes a correct unit?

9702_s15_qp_13

MCQ

2015

Paper 1, Variant 3

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An electron moves between two points X and Y in a uniform electric field, as shown...

9702_w17_qp_12

MCQ

2017

Paper 1, Variant 2

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Questions Discovered

18