Magnetic Effect Of Electric Current
Key Notes :
Introduction to Magnetism:
- Magnetic fields are produced around a magnet, and these fields affect magnetic materials (such as iron, nickel, and cobalt).
- Electric current produces a magnetic field around a conductor (like a wire).
Oersted’s Discovery:
- Hans Christian Oersted discovered that a current-carrying wire creates a magnetic field around it.
- This phenomenon is known as the magnetic effect of electric current.
Magnetic Field Around a Conductor:
- A current-carrying wire generates a circular magnetic field around it.
- The direction of the magnetic field can be determined using the right-hand thumb rule:
- If the right hand’s thumb points in the direction of the current, the curled fingers show the direction of the magnetic field.
Electric Motor:
- The magnetic effect of current is used in electric motors.
- In a motor, a coil carrying current is placed in a magnetic field. The interaction between the magnetic field and the current causes the coil to rotate.
Solenoid:
- A solenoid is a coil of wire, usually wound around a cylindrical object, through which electric current passes.
- The magnetic field inside a solenoid is strong, uniform, and resembles that of a bar magnet.
- A solenoid is used in devices like electromagnets and electric bells.
Electromagnet:
- An electromagnet is made by wrapping a wire around a soft iron core and passing a current through the wire.
- The strength of the magnetic field depends on the number of turns of the wire, the current, and the material of the core.
- Electromagnets are used in cranes to lift heavy metallic objects, in electric motors, and in MRI machines.
Factors Affecting the Magnetic Effect:
- The strength of the magnetic field is affected by:
- The amount of current (greater current = stronger magnetic field).
- The number of turns in the coil (more turns = stronger magnetic field).
- The presence of a core material (a soft iron core strengthens the magnetic field).
Magnetic Field and Force:
- A current-carrying conductor placed in a magnetic field experiences a force. This is the basis of how electric motors work.
- The direction of the force can be determined using the left-hand rule:
- Point the left hand’s fingers in the direction of the magnetic field, the thumb in the direction of the current, and the palm shows the direction of the force on the conductor.
Let’s practice!
