Solenoid

A Coil of many circular turns of insulated copper wire wrapped closely in the shape of a cylinder is called solenoid.

Magnetic field due to a current in a solenoid

Using Right Hand Thumb Rule, we can draw the pattern of magnetic field lines around a current carrying ‘Solenoid’.

One end of the solenoid behaves as a magnetic north pole, while the other end behave as the South Pole.

The filed lines inside the solenoid are in form of parallel straight lines, that implies that magnetic field inside the solenoid is same at all points i.e. Field is uniform.

The strength of the magnetic field produced depends upon

• the number of turns
• Strength of current in the solenoid used in making solenoid.

Electromagnet

Strong magnetic field inside the solenoid can be used to magnetize a magnetic material for example soft iron, when it is placed inside the coil. The magnet so formed is called electromagnet. It is a temporary magnet.