In order to create an electromagnet, you would ?

Electromagnet is an temporary magnet produced when electric current is passed through specific materials.

The process of production of electromagnet is explained as follows :

From Oersted's law, we know that a current carrying conductor produces a magnetic field around it.

The same principle is applied in the production of electromagnet.

A ferromagnetic material is wound by insulated copper wires. The current is allowed to pass through wounded ferromagnetic material which in turn, produces magnetic field around it, and acts just like a strong electromagnet.

The magnetism is retained as long as there is current flow in the wire.

the answer is b ) square root of 5

what is the question because that is not a question.