What is another name for electromagnetic induction?

• The motor effect

• The generator effect

• A solenoid

• A flux capacitor

How can the direction of an induced potential be reversed?

• By changing the direction of the magnetic field

• By using fewer coils

• By moving the magnet faster

• By changing the direction of the magnetic field, and moving the magnet in the opposite direction

How is contact between the coil and circuit maintained in an alternator?

• A split ring commutator connects to each side for half a turn

• It cannot be maintained.

• The alternator can only complete one revolution and must then be rotated in reverse

• Slip rings and brushes allow continuous connection

What is the voltage from an alternator half a turn after maximum positive output?

• Half the maximum output

• Maximum positive output again

• Zero voltage

• Maximum negative output

How can the voltage output from an alternator be doubled?

• Halve the speed of rotation but reverse the direction of rotation

• Double the speed of rotation

• Reverse the direction of rotation

• Use half the number of coils

The voltage from a dynamo changes as the coil turns. What is the voltage one half turn after the maximum positive output?

• Half the maximum output

• Maximum positive output again

• Zero voltage

• Maximum negative output

How can the voltage output from a dynamo be doubled?

• Reverse the direction of rotation

• Halve the speed of rotation but reverse the direction of rotation

• Double the speed of rotation

• Use half the number of coils

In a dynamo, what is the function of the split ring commutator?

• It strengthens the magnetic field to make a greater output current for the same rotation speed

• It reverses the connections every half turn, to keep the output current alternating every half turn

• It reverses the coil connections every half turn, to keep the output current in the same direction all the time

• It prevents the coil from overheating

What is the function of a microphone?

• It converts sound waves into electrical signals

• It converts electrical signals into sound waves

• It converts alternating current signals into direct current signals

• It converts direct current signals into alternating current signals

How does a moving-coil microphone create electrical signals?

• An electromagnet vibrates inside a coil of wire

• A coil of wire vibrates in a magnetic field

• A magnet vibrates inside a coil of wire

• A small battery vibrates in a circuit