Uses of generators (triple only)

Question 1

Describe how an alternator uses the generator effect

Answer 1

A spinning coil in a magnetic field produces an alternating current

Question 2

State the type of current produced by the generator effect in a dynamo?

Answer 2

Direct current

Question 3

Explain how a dynamo keeps the current flowing in the same direction

Answer 3

The split ring commutator makes the ends of the coil change from positive to negative (and back) every half turn

Question 4

State when the induced potential difference produced by an alternator is at a maximum

Answer 4

When the plane of the coil is parallel to the magnetic field lines (the coil is passing through the most magnetic field lines)

Question 5

What does a transformer do?

Answer 5

changes the magnitude of the alternating p.d.

Question 6

What does a basic transformer consist of?

Answer 6

two coils of wire wound around an iron core

Question 7

Why is iron used for the core of a transformer?

Answer 7

iron is easily magnetised and demagnetised

Question 8

How does a transformer work?

Answer 8

alternating p.d. across the primary coil produces an alternating magnetic field in the iron core which induces an alternating p.d. in the secondary coil

Question 9

How is the ratio of p.d. across the primary coil and secondary coil related to the ratio of the number of turns on each coil?

Answer 9

the ratios are the same

Question 10

Which type of transformer has more turns on its secondary coil than on its primary coil?

Answer 10

step-up transformer

Question 11

What is the efficiency of a transformer if the power output from the secondary coil is the same as the power input to the primary coil?

Answer 11

100%