Electrodynamics
, Magnetic field around a straight conductor
- When an electric current flows through a straight current carrying conductor, a magnetic field
originates around that conductor
- Magnetic field lines = lies as concentric circles around the conductor at a ⊥
- Magnetic field = strongest closer to the conductor & weaker the further you go
- Direction of magnetic field = determined using The Right hand rule
Right hand rule: Hold the conductor in your right hand so
that the thumb points in the direction of a current. The
direction in which your fingers are bending will be the
direction of the magnetic field
The Motor Effect
- Motor effect: When current carrying conductor = placed inside another magnetic field, the two magnetic
fields interact with eachother through attraction/repulsion and the conductor EXPERIENCES a force and
therefore moves in a specific direction
- The direction of the force can be determined using Flemming's left hand motor rule
Flemming's left hand rule: Place the index finger, middle finger and thumb
of you left hand ⊥ to eachother. When your index finger points in the
direction of the magnetic field and your middle finger in the direction of the
conventional current, your thumb will indicate the direction of the force
The Solenoid
- A solenoid is a large number of insulated coils/turnings/windings that forms a cylindrical set up
- If current flows through a solenoid = magnetic field = Also have N and S pole
- Direction of magnetic field outside solenoid = N -> S
- Direction of magnetic field inside solenoid = S -> N
- The poles are determined using the Right hand Solenoid rule
Right hand Solenoid Rule: Hold the solenoid in your right hand,
with bent fingers pointing in the direction of the conventional
current, the extended thumb points in the direction of the N-
pole of the solenoid
, Magnetic field around a straight conductor
- When an electric current flows through a straight current carrying conductor, a magnetic field
originates around that conductor
- Magnetic field lines = lies as concentric circles around the conductor at a ⊥
- Magnetic field = strongest closer to the conductor & weaker the further you go
- Direction of magnetic field = determined using The Right hand rule
Right hand rule: Hold the conductor in your right hand so
that the thumb points in the direction of a current. The
direction in which your fingers are bending will be the
direction of the magnetic field
The Motor Effect
- Motor effect: When current carrying conductor = placed inside another magnetic field, the two magnetic
fields interact with eachother through attraction/repulsion and the conductor EXPERIENCES a force and
therefore moves in a specific direction
- The direction of the force can be determined using Flemming's left hand motor rule
Flemming's left hand rule: Place the index finger, middle finger and thumb
of you left hand ⊥ to eachother. When your index finger points in the
direction of the magnetic field and your middle finger in the direction of the
conventional current, your thumb will indicate the direction of the force
The Solenoid
- A solenoid is a large number of insulated coils/turnings/windings that forms a cylindrical set up
- If current flows through a solenoid = magnetic field = Also have N and S pole
- Direction of magnetic field outside solenoid = N -> S
- Direction of magnetic field inside solenoid = S -> N
- The poles are determined using the Right hand Solenoid rule
Right hand Solenoid Rule: Hold the solenoid in your right hand,
with bent fingers pointing in the direction of the conventional
current, the extended thumb points in the direction of the N-
pole of the solenoid
