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 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
What is the potential difference from an alternator half a turn after maximum positive output?
Maximum negative output
Maximum positive output again
Zero potential difference
How can the potential difference 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 potential difference from a dynamo changes as the coil turns. What is the potential difference one half turn after the maximum positive output?
How can the potential difference output from a dynamo be doubled?
Which of these equations correctly links potential differences and number of turns on the coils in transformers?
\[\frac{V_{p}}{V_{s}} = \frac{n_{s}}{n_{p}}\]
\[V_{s} \times n_{s} = V_{p} \times n_{p}\]
\[V_{s} \times n_{p} = V_{p} \times n_{s}\]
What kind of transformer converts 230,000 V into 11,500 V?
Step-down
Step-out
Step-up
A transformer has 420 turns on its primary coil. How many turns on the secondary coil are needed for it to increase the potential difference by a factor of three?
140
420
1,260