Quelpr
3 marksMagnetic Forces

CAPE Physics Unit 2 · 2004 · Paper 2 · Question 5(b)(iii)

An electron moving with velocity v perpendicular to a uniform magnetic field B directed out of the page, as shown in Figure 5.

Show that the path described by the electron in the magnetic field is a circle of radius r given by r = mv / (Be), where m is mass of electron and e is electron charge.

This question uses a figure or table from the paper — you'll see it when you practise.

The mark scheme is shown once you've answered.

Practise this question

Other parts of this question

  1. 5(a)Explain, with the aid of a diagram, Fleming's Left Hand Rule.[3 marks]
  2. 5(b)(i)Copy Figure 5 into your answer booklet and draw the path of the electron as it passes through the magnetic field. On the same diagram, draw the path if the…[3 marks]
  3. 5(b)(ii)Explain what work is done on the electron as it passes through the magnetic field.[2 marks]
  4. 5(b)(iv)On the Figure 5 copied in your answer booklet, draw the path of the electron if the magnetic field B was reduced to half its value.[2 marks]
  5. 5(c)Determine the mass, m_x, of the second particle.[7 marks]

More practice: the rest of this paper · more Magnetic Forces questions · all CAPE Physics Unit 2 past papers