P2P12 - Electromagnetism + Motor effect Flashcards
Whats the magnetic field inside a solenoid like?
Strong and uniform.
What is the motor effect?
When a wire with a current flowing through it is placed in a magnetic field, the magnet and the conductor will experience a force.
What does the motor effect cause?
Force experienced by current-carrying wires in magnetic fields
What does Fleming’s left hand rule determine?
The direction of the force
What does the thumb represent?
Force
What does the middle finger represent?
Current
What does the pointer finger represent?
Magnetic field
What is the catapult experiment?
The catapult experiment shows that a wire carrying a current in a magnetic field experiences a force.
When power supply is on, a current flows in the free wire and so this wire feels a force and moves.
Swapping the north and south poles of the magnet will reverse the wire’s direction of movement.
Swapping the wires connecting to the power supply reverses the direction of the current.
Reversing the direction of the current will reverse the direction that the wire moves.
How do you calculate the force produced?
Force produced =
Magnetic flux density × current × length of conductor.
F = B x I x L.
What is Magnetic flux density measured in?
Tesla
What does a split ring commutator do?
Reverses the direction of the current every half-turn of the coil.
How do loudspeakers work?
As the direction of the current changes, the direction of the magnetic field induced in the electromagnet changes.
A stationary magnet repeatedly attracts and repels the electromagnet.
Speakers vibrate
Sound is created
What are ways to increase the turning force on a current carrying coil of wire in a magnetic field?
Increase magnetic field
Increase n.o of coils
Increase current
