4.7 Magnetism and electromagnetism Flashcards
(8 cards)
What is a magnetic field?
A region around a magnet where magnetic materials experience a force.
What is the shape of the magnetic field around a straight current-carrying wire?
Concentric circles centered on the wire, with the direction given by the right-hand rule.
What is the motor effect?
The force experienced by a current-carrying conductor in a magnetic field, which is used in electric motors.
What is Fleming’s left-hand rule?
A rule to determine the direction of force on a current-carrying conductor in a magnetic field: thumb represents force (motion), first finger represents magnetic field, and second finger represents current.
What is electromagnetic induction?
The process of generating an electromotive force (emf) by changing the magnetic field around a conductor.
What factors affect the size of the induced potential difference?
The speed of movement, the strength of the magnetic field, and the number of turns in the coil.
What is a transformer?
A device that changes the potential difference of an alternating current using electromagnetic induction, consisting of primary and secondary coils wound on an iron core.
What is the equation for transformer efficiency?
For an ideal transformer: Vp × Ip = Vs × Is, where V is voltage, I is current, and subscripts p and s refer to primary and secondary coils, respectively.
