SOLENOIDS

1.The solenoid is a long coil containing a large number of close turns of insulated copper wire. 

2.The magnetic field produced by a current carrying solenoid is similar to the magnetic field produced by a bar magnet.

3. The lines of magnetic force pass through the solenoid and return to the other end. 

4.If a current carrying solenoid is suspended freely, it comes to rest pointing North and South like a suspended magnetic needle.

5. One end of the solenoid acts like a N-pole and the other end a S-pole. 

6.Since the current in each circular turn of the solenoid flows in the same direction, the magnetic field produced by each turn of the solenoid adds up, giving a strong resultant magnetic field inside the solenoid. 

7.A solenoid is used for making electromagnets.

8.The strength of magnetic field produced by a current carrying solenoid is:

• Directly proportional to the number of turns in the solenoid
• Directly proportional to the strength of current in the solenoid
• Dependent on the nature of "core material" used in making the solenoid. The use of soft iron rod as core in a solenoid produces the strongest magnetism.