Year 12 PhysicsPage 1

Unit 3 – Electronics Revision

WS #1

Question 1

A circuit consists of three identical lamps connected to a battery with a switch as shown in the diagram. When the switch is closed what happens:

a)to the intensity of lamp A?

b) to the intensity of lamp C?

c) to the current in the circuit?

d) to the potential difference across lamp B?

e) to the potential difference across lamp C?

f) to the total power dissipated in the circuit?

Question 2

In the following three circuits the batteries and resistors are all identical.

a) Which resistor(s) has the highest current flowing through it?

b) Which resistor(s) has the lowest current flowing through it?

c) Which resistor(s) has the highest power dissipated through it?

Question 3

a) For the following circuits, which of the following statements is correct? Assume the ammeters are identical.

A) Ammeter X displays the highest current.

B) Ammeter Y displays the highest current.

C) Both ammeters display the same current.

b) For the following circuits, which of the following statements is correct? Assume the voltmeters are identical.

A) Voltmeter X displays the higher voltage drop.

B) Voltmeter Y displays the higher voltage drop.

C) Both voltmeters display the same voltage.

Question 4

A voltmeter is used to measure the voltage (relative to ground] at various points around a circuit. The voltages at points X and Y are as shown in the diagrams.

For circuits (a) and (b) determine the magnitude and direction (P or Q) for the current flowing through the 5 k resistor and the 2 k resistor.

Question 5

The following circuit is a simple voltage divider consisting of two variable resistors of resistance R1 and R2. Complete the table.

R1 / R2 / Vout
1000 / 10
1000 / 5.0
400 / 100
900 / 2.0
2.0 / 3.0

Question 6
Three variable resistors R1, R2 and R3 are connected to a switch S. Determine the values of Vout in the table.

R1 / R2 / R3 / S / Vout
200 / 200 / 100 / Open
300 / 100 / 25 / Open
50 / 50 / 75 / Open
100 / 100 / 1000 / Open
200 / 100 / 100 / Closed

Question 7

The graph (below) represents a plot of potential difference (V) as a function of position (clockwise from X) around the electronic circuit (below). Assume all wires and the switch have zero resistance.

Sketch the potential difference versus position graphs for the following circuits.

The following information applies to questions 8-10.

A manufacturer makes two different globes for a 12.0 V torch:

one is rated at 0.50 W and the other at 1.00 W.

Question 8

What is the resistance of each globe when it is operating correctly?

Question 9

If the two globes are connected in parallel across a 12.0V supply:

a which has the greater potential difference across it? b which has the greater current through it? c which glows more brightly?

Question 10

If the two globes are connected in series across the 12.0V supply:

a which has the greater potential difference across it?

b which has the greater current through it?

c which glows more brightly?

Question 11*

Consider the circuit shown.

a Determine the total resistance connected across the battery terminals.

b Determine the voltage across the 40 k resistor.

c Determine the current through the 5 k resistor.

d Determine the voltage across the 20 k resistor.

Year 12 PhysicsPage 1

Unit 3 – Electronics Revision

WS #1