Two large flat magnets are placed with their faces parallel and 4 cm apart.
The north pole of the left-hand magnet faces the south pole of the right-hand magnet.
Describe the magnetic field in the central region between the two magnets.
State what is meant by a uniform magnetic field.
The right-hand magnet is turned round so that two north poles face each other.
Describe how the force between the magnets changes.
Give a reason for your answer.
The magnets are put back in their original positions.
A student draws the field around the magnets. The student then counts the number of field lines crossing a 1 cm line at three positions, P, Q and R.
The Table shows the results.
Table
| Position | Number of field lines crossing a 1 cm line |
|---|---|
| P (centre of the gap) | 6 |
| Q (near the edge of the gap) | 6 |
| R (outside the gap) | 2 |
Explain what the Table shows about the strength of the magnetic field at P, Q and R.