Sunday, 21 September 2014

RESISTANCE, POTENTIAL DIFFERENCE AND CURRENT CALCULATIONS







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?