A student has three metal rods, P, Q and R, that look the same.
One rod is a permanent magnet. One rod is unmagnetised iron. One rod is aluminium.
The student brings the north pole of a bar magnet close to each end of each rod in turn.
The Table shows the results.
Table
| Rod | Effect on end 1 | Effect on end 2 |
|---|---|---|
| P | attracted | repelled |
| Q | attracted | attracted |
| R | no effect | no effect |
Identify which rod is the permanent magnet.
Give a reason for your answer.
Explain why the student cannot use attraction alone to decide whether a rod is a permanent magnet.
Explain what the result for rod R shows about the material that rod R is made from.
The student writes:
'End 1 of rod P is a north pole.'
Explain why the student is wrong.