Solenoid: A solenoid is a coil comprising numerous circular turns of insulated copper wire coiled on a cylindrical insulating body (i.e., cardboard, etc.) so that its length exceeds its diameter.
When current flows through the solenoid, the magnetic field line pattern closely matches that of a bar magnet with fixed polarity, i.e. a North and South pole at each end, and it develops directive and attracting qualities similar to that of a bar magnet.
As a result, the current-carrying solenoid acts like a bar magnet.
Current-carrying solenoid is used to create a transient magnet known as an electromagnet, as well as a permanent magnet.
Final Answer
A solenoid is a coil comprising numerous circular turns of insulated copper wire coiled on a cylindrical insulating body (i.e., cardboard, etc.) so that its length exceeds its diameter.
An electromagnet is a current-carrying solenoid.
