What is another name for electromagnetic induction?
The motor effect
The generator effect
A solenoid
How can the direction of an induced potential be reversed?
By changing the direction of the magnetic field
By moving the magnet faster
By changing the direction of the magnetic field, and moving the magnet in the opposite direction
How can the induced current be increased?
Increase the number of turns in the coil
Increase the applied current
Make the permanent magnet larger in size
How is contact between the coil and circuit maintained in an alternator?
Slip rings and brushes allow continuous connection
The alternator can only complete one revolution and must then be rotated in reverse
A split ring commutator connects to each side for half a turn
How would an alternator be suitable for use in a car?
To act as a backup if the petrol runs out
To let you listen to the radio while the engine is off
To keep the battery charged
What is the voltage from an alternator half a turn after maximum positive output?
Maximum negative output
Maximum positive output again
Zero voltage
How can the voltage output from an alternator be doubled?
Reverse the direction of rotation
Double the speed of rotation
Halve the speed of rotation but reverse the direction of rotation
The voltage from a dynamo changes as the coil turns. What is the voltage one half turn after the maximum positive output?
How can the voltage output from a dynamo be doubled?
In a dynamo, what is the function of the split ring commutator?
It reverses the coil connections every half turn, to keep the output current in the same direction all the time
It reverses the connections every half turn, to keep the output current alternating every half turn
It strengthens the magnetic field to make a greater output current for the same rotation speed