User interface language: English | Español

Date May 2019 Marks available 1 Reference code 19M.3.HL.TZ2.8
Level Higher level Paper Paper 3 Time zone 2
Command term Define Question number 8 Adapted from N/A

Question

A proton has a total energy 1050 MeV after being accelerated from rest through a potential difference V.

Define total energy.

[1]
a.

Determine the momentum of the proton.

[1]
bi.

Determine the speed of the proton.

[2]
bii.

Calculate the potential difference V.

[1]
biii.

Markscheme

total energy is the sum of the rest energy and the kinetic energy

a.

«p2 c2 = 10502–9382 therefore» p=472«MeVc1»

bi.

γ = 1050 938 = 1.12  ✔

v = 0.45 c

OR

V = 1.35 × 10 8 «ms–1»  

 

bii.

V = 112 «MV» ✔

biii.

Examiners report

Generally well answered by most candidates. A common mistake was to define the total energy in the context of classical mechanics.

a.

Most candidates seemed to have the right starting points but mistakes were often made in attempting to convert units. The energy-momentum equation is generally best answered using only ‘MeV’ based units.

bi.

An easy calculation, that was generally well answered.

bii.

Very few candidates realised that this question required a simple calculation using eV= KE = (γ-1)E.

biii.

Syllabus sections

Option A: Relativity » Option A: Relativity (Additional higher level option topics) » A.4 – Relativistic mechanics (HL only)
Show 27 related questions
Option A: Relativity » Option A: Relativity (Additional higher level option topics)
Option A: Relativity

View options