DP Physics (last assessment 2024)

Question 18M.3.HL.TZ1.a.ii

Date	May 2018	Marks available	[Maximum mark: 2]	Reference code	18M.3.HL.TZ1.a.ii
Level	HL	Paper	3	Time zone	TZ1
Command term	Show that	Question number	a.ii	Adapted from	N/A

a.ii.

[Maximum mark: 2]

18M.3.HL.TZ1.a.ii

A positive pion decays into a positive muon and a neutrino.

${\pi ^ + } \to {\mu ^ + } + {v_\mu }$

The momentum of the muon is measured to be 29.8 MeV c^–1 in a laboratory reference frame in which the pion is at rest. The rest mass of the muon is 105.7 MeV c^–2 and the mass of the neutrino can be assumed to be zero.

For the laboratory reference frame

show that the energy of the pion is about 140 MeV.

[2]

Markscheme

E_π = $\sqrt {p_\mu ^2{c^2} + m_\mu ^2{c^4}}$ + p_vc OR E_μ = 109.8 «MeV»

E_π = « $\sqrt {{{29.8}^2} + {{105.7}^2}}$ + 29.8 =» 139.6 «MeV»

Final value to at least 3 sig figs required for mark.

[2 marks]

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Option A: Relativity

Option A: Relativity » Option A: Relativity (Additional higher level option topics) » A.4 – Relativistic mechanics (HL only)

Option A: Relativity » Option A: Relativity (Additional higher level option topics)

Question 18M.3.HL.TZ1.a.ii

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