Induction hobs work by following the Faraday’s law of electromagnetic induction. This is where a magnetic field is created between two surfaces. This is why cooking with an induction hob requires the use of a special pan.
This pan should be made of a Ferromagnetic material. Cast iron is so far the best material from which an induction pan should be made.
The easiest way to tell if your pan can be used on an induction hob is by carrying out the magnet test. It is also very easy to do this test because all you need is a piece of magnet and the pans you need to test. Bring the magnet close to the bottom of the pan and see if it sticks. If it does, the pan is induction hob compatible. If, on the other hand, the magnet does not stick at all to the bottom of the pan, then the pan is not induction hob compatible. You may find that with some pans the magnet sticks but only loosely and can be easily shaken off. What this means is that the pan is made of a poor ferromagnetic material and can lead to poor cooking results.
There are three types of induction hob compatible pans.
Pure iron pans are the best induction hob-compatible pans. Iron alloys have only a proportion of iron in the material and therefore could be good or bad depending on the proportion of iron used. For those pans that are made of other materials such as aluminum, copper or glass, they will have to be coated with a magnetic material at the bottom in order to be induction hob-compatible.
The other way you can test if your pans are compatible with an induction hob is by using them to use with an induction hob. If the pan does not heat up at all or takes a long time to heat up, then it means the pan is not compatible or it is made of a poor ferromagnetic material. But if the pan heats up in a considerably short time, then it is a good pan to use for cooking on an induction hob.
In summation, a magnet test is the best, reliable and fast way to tell if you can use your current pan on an induction hob.