A Level Physics Session

Gravitation Waves and Interference Magnetic Force Photoelectric Effect

Magnetic Force

Hi Everyone,

Welcome to this session on magnetic force on electric current. The following are two videos on this topic.

207 Magnetic force on moving charge 2

208 Magnetic force on moving charge 3


Please try these questions.

  1. Suppose that there are 8.5x1028 conduction electrons per m³ of copper. A piece of copper wire has a cross-sectional area of 1 mm². A current of 0.1 A flows through it. How many electrons flow past a point P on the wire in 1 s?

  2. Find the volume of copper that contains this number of electrons. Find the length of the copper wire that contains has the same volume.

  3. Since the conduction electrons in this length of the wire flows past point P in 1 s, find the average velocity of these electrons.

  4. Find the force on this length of wire if a magnetic flux density of 0.1 T is at right angle to it.

  5. Using this force, find the average force on one conduction electron.

  6. Find this force again using F = BQv.

Past Exam Questions

In this video, I shall go through some questions from a past exam paper.

2012 H2 Physics P1 27

2012 H2 Physics P1 34

Thanks for attending this session.

Dr Hock
5 May 2014