1After switching off, take the magnet out of the solenoid with the pliers and bring it near the pins. What happens, and why does it happen?
2What is demagnetisation? Explain it in terms of molecular magnets.
3Why does a magnet lose its magnetic power when it is heated?
4What happens inside a magnet when it is hammered or dropped again and again?
5How does alternating current destroy a magnet's magnetic power?
6What is meant by natural loss of magnetic power?
7Write down four ways of protecting a magnet's magnetic power.
8A bar magnet that has lain loose in a drawer for years no longer picks up pins. Give the likely reasons and say how such a magnet should be looked after from now on.