A circuit contains five identical resistors and four identical voltmeters. The reading on voltmeter V1 is 8.0 V and the reading on voltmeter V2 is 1.0 V. What are the readings on V3 and V4?
|
reading on voltmeter V3 / V |
reading on voltmeter V4 / V |
|
|
A. |
1.5 |
1.0 |
|
B. |
3.0 |
2.0 |
|
C. |
4.5 |
3.0 |
|
D. |
6.0 |
4.0 |
A power cable X has resistance R and carries current I. A second cable Y has resistance 2R and carries current 
.
What is the ratio 
?
2
4
Two resistors are connected to a cell.
Assuming both resistors are made from wires of the same length, which graph shows how the potential V varies along the line XY?
Kirchhoff’s laws are applied to the circuit shown.
What is the equation for the dotted loop?
0 = 2I3 – 3I2
0 = 2I2 – 3I3
6 = 3I2 + 2I3 + 2I1
6 = 3I2 + 2I3
In the circuit shown, the fixed resistor has a value of 3 Ω and the variable resistor varies between 0 Ω and 12 Ω.
The power supply has an emf of 15 V and negligible internal resistance.
What is the range of potential differences V which can be measured across the 3 Ω resistor?
3 V
6 V
9 V
12 V
Four resistors are connected to a battery of e.m.f. 6 V as shown.
If the battery has negligible internal resistance, what is the current in the battery?
2 A
3 A
4 A
5 A
Which of the following cannot be the units for resistivity?
V m A–1
J m s–1 A–1
J m s–1 A–2
Ω m
Three resistors are connected to a cell of e.m.f. 10 V and negligible internal resistance as shown.
What is the power dissipated in one of the 2 Ω resistors and in the whole circuit?
|
power dissipated in the 2 Ω resistor / W |
power dissipated in the whole circuit / W |
|
|
A |
1 |
18 |
|
B |
1 |
20 |
|
C |
2 |
18 |
|
D |
2 |
20 |
Three identical lamps, W, X and Y are connected to a cell of negligible internal resistance as shown.
When the switch is closed, each lamp is lit. Which of the following correctly describes the brightness of lamps W, X and Y when the switch is opened?
|
lamp W |
lamp X |
lamp Y |
|
|
A |
increases |
increases |
decreases |
|
B |
decreases |
off |
decreases |
|
C |
decreases |
off |
increases |
|
D |
increases |
decreases |
decreases |
A science student who lives in the UK, where the mains voltage is 240 V, buys a light bulb marked 60 W which she uses in her bedroom. The student takes the lightbulb with her on a trip to Canada where the mains voltage is 100 V and also uses it there.
Which line correctly identifies the approximate power dissipated in the bulb in the UK and Canada?
| UK / W | Canada / W | |
| A. | 30 | 10 |
| B. | 60 | 30 |
| C. | 60 | 10 |
| D. | 120 | 60 |
