## 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

### Exercises

Please try these questions.-
Suppose that there are 8.5x10
^{28}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.

### Past Exam Questions

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

Thanks for attending this session.

Dr Hock

5 May 2014