ConceptConceptDocsDocuments

CAIE IGCSE Physics Magnetic Force on Charged-Particle Beams

Practise predicting magnetic deflection of electron and alpha-particle beams from velocity and field directions, accounting for the particle's charge sign.

Syllabus
2026–2028
Course
Physics 0625

Exam points

  • treat the motion of positive particles as conventional current when applying the direction rule
  • reverse the force direction obtained for positive current when the moving particle is an electron
  • state that a charged beam is forced only when its motion has a component across the magnetic field

4.5.4.3—Direction of the force on beams of question 1

[Maximum number: 3]

An electron source produces a narrow beam of electrons that all travel at the same speed.

The electron source is placed in a vacuum and the beam of electrons travels vertically downwards. Fig. 7.1 shows the beam of electrons before it passes between the N -pole and the S-pole of a magnet.

Fig. 7.1

Fig. 7.1

Describe and explain what happens to the beam of electrons in the magnetic field between the poles of the magnet in Fig. 7.1.

All question bank results loaded