Definition of Electromagnetic Induction?
Electromagnetic induction is the production of __________ and __________ due to the change of _______ or the _________ of magnetic flux
Electromagnetic induction is the production of induced EMF and induced current due to the change of magnetic flux or cutting of magnetic flux
What can we use to determine the direction of induced current
Fleming’s Right Hand Rule
Thumb : Motion of conductor
Fore Finger : Direction of magnetic field
Middle Finger : Direction of induced current
How can we determine the direction of current?
Galvanometer
Catapult force
Force produced when magnetic field and current interact.
What happens when the conductor is moved horizontally and parallel to the magnetic field?
( To and Fro )
No induced current produced
What happens when the conductor is moved horizontally perpendicular to the magnetic field?
( side to side)
No induced current produced
Study the electromagnetic induction in a solenoid
What is the reading of the galvanometer when the conductor is pulled out of solenoid?
Galvanometer deflects to the opposite side of conductor going in. To show the opposite direction of current.
What is observed when the conductor is stationary in the solenoid?
No reading is observe on the galvanometer
Name factors that affect the reading of galvanometer
- Number of turns on the solenoid
- Speed of relative motion
- Strength of magnetic field
How is electromagnetic induction produce?
- When straight wire moved downwrds, the conductor cuts through the magnetic flux
- cutting of magnetic flux produces induced EMF causes induced current to flow in the conductor
State the law that reveals that induced electric current always flows in such a direction so as to oppose the change of motion causing it.
Lenz’s Law
What happens when the North Pole of magnet move towards solenoid?
Solenoid becomes north pole where the magnet move towards it.
Hence it will produce force of repulsion to oppose the change the motion of the bar magnet which produces it.
What happens when the South Pole of magnet move towards solenoid?
- the solenoid becomes south pole
- produce a force of repulsion
What happens when the north pole move away from solenoid?
- solenoid will be south pole when bar magnet’s north pole moves away
- hence it produces a force of attraction
- this produces an induced current
- direction of current is reversed and galvanometer deflect to the opposite direction
What happens when the south pole of bar magnet is moved away from solenoid?
- When south Pole is moved away from the solenoid, the solenoid becomes north pole
- it produces a force of attraction
Faraday’s Law states that……
Faraday’s Law state that the magnitude of the induced EMF is directly proportional to the rate of cutting of magnetic flux.
What are the factors affection the magnitude of induced EMF?
- number of turn of solenoid
- strength of magnetic field
- the speed of the relative motion
How does the speed of relative motion affects the induced current?
- speed of motion increase
- cutting of magnetic flux increase
- induced current increase
How does the strength of magnetic field affects the induced current?
- strength of magnetic field increase
- the more the magnetic field lines produced
- cutting of magnetic flux increases
- induced current increases
How does the number of turns affect the induced current?
- number of turns increase
- more cutting of magnetic field lines at the same time
- more induced current is produced
Compare the DC generator and AC generator.
Similarities:
- both uses electromagnetic induction
Differences:
- DC generator - AC generator
1.End coil connected to 1.End coil
split ring commutator connected to slip
rings (2 rings)
- Two sections of commutator 2. Slip rings are
exchange contact with carbon connected to the
brushes every half rotation same carbon brush - Output is direct current 3. Output is
Alternating current
