A Level Physics Session

Magnetic Force

Hi Everyone,

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

Please try these questions.

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?
Find the volume of copper that contains this number of electrons. Find the length of the copper wire that contains has the same volume.
Since the conduction electrons in this length of the wire flows past point P in 1 s, find the average velocity of these electrons.
Find the force on this length of wire if a magnetic flux density of 0.1 T is at right angle to it.
Using this force, find the average force on one conduction electron.
Find this force again using F = BQv.

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

Thanks for attending this session.

Dr Hock
5 May 2014