|
|
RESISTANCE
|
POTENTIAL
DIFFERENCE
|
CURRENT
|
WORKING
OUT
|
ANSWER
(WITH UNITS)
|
|
1
|
?
|
30 V
|
5 A
|
|
|
|
2
|
?
|
240 V
|
1.5 A
|
|
|
|
3
|
60 W
|
?
|
0.4 A
|
|
|
|
4
|
2,000 W
|
6 V
|
?
|
|
|
|
5
|
0.5 W
|
4.5 V
|
?
|
|
|
|
6
|
?
|
12 V
|
400 mA
|
|
|
|
7
|
330 W
|
?
|
4.5 A
|
|
|
8. A student is performing an experiment
to measure the resistance of a
piece of wire. The reading on the
ammeter is 3.7 A and the reading on
the voltmeter is 12.5 V. What is the
resistance of the piece of wire?
9. When a man touches a live cable the pd
between him and the earth is
3,000 V. If his body has an
effective resistance of 5 kW,
what is the
Current that flows through his body?
10. A student connects up a circuit with a
battery, bulb and ammeter in
series. The resistance of the bulb
is 4.6 W and the
reading on the
ammeter is 1.2 A. When he is
connecting a voltmeter across the bulb
should
he use the 0 – 5 V scale or the 0 – 15 V scale?