Magnetic effect of Electric Current
In other Words,
Magnetic Field Lines
The magnetic field lines are also known as magnetic lines of force.
Properties of the Magnetic Field Lines
- The magnetic field lines originate from the north pole of the magnet and end at its south pole.
- The magnetic field lines come closer to one another near the poles of a magnet but they are widely separated at other places.
- The magnetic field lines do not intersect (or cross) one another.
Magnetic Field of Earth
- The axis of earth’s magnet and geographical axis do not coincide with each other.
- The axis of earth’s magnetic field is inclined at an angle of about 15 degree with the geographical axis.
- The earth magnetism is due to the magnetic effect of current (which is flowing in the liquid core at the centre of the earth). Thus, Earth is huge electromagnet.
Magnetic Effect of Current or Electromagnetism
Magnetic Field Pattern due to a Circular loop
- Directly proportional to the current passing through the circular loop (or circular wire), and
- inversely proportional to the radius of circular loop (or circular wire).
Clock Face Rule
- If the current around the face of circular wire (or coil) flows in a Clockwise direction, then that face of a circular wire will be South pole (S-pole).
- If the current around the face of circular wire flow in the Anticlockwise direction, then that face of circular wire will be a North pole (N-pole).
Note: If the direction of current in the front face of circular wire is clockwise, then the direction of current in the back face of the circular wire will be anticlockwise.
Magnetic Field Due to Solenoid
- The number of turns in the solenoid. Larger the number of turns in the solenoid, greater will be the magnetism produced.
- The strength of current in the solenoid . Larger the current passed through solenoid, stronger will be the magnetic field produced.
- The nature of “core material” used in making solenoid. The use of soft iron rod as core in a solenoid produces the strongest magnetism.
An electromagnets works on the magnetic effect of current.
An electromagnet is a magnet consisting of a long coil of insulated copper wire wrapped around a soft iron core that is magnetised only when electric current is passed through the coil.
The core of an electromagnetic must be of soft iron because soft loses all of its magnetism when current in the coil is switched off.