The diagram shows a circuit with a 2 kΩ resistor and a lamp connected in parallel, and a voltmeter connected across the lamp.
If the reading on the voltmeter is 3 V, how much power is dissipated in the resistor?
1.5 W
0.66 W
4.5 × 10–3 W
4.5 W
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The diagram shows two identical 2 Ω resistors arranged in parallel.
What is the reading on the ammeter?
6 A
1.5 A
1 A
12 A
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The circuit symbol for a battery is a set of cells in series:
If the dashed lines represent an additional 8 cells, and each cell provides an emf of 0.5 V, what is the total emf provided by the battery?
1 V
4 V
5 V
6 V
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A 60 W house lamp is accidentally left on overnight.
How much energy is transferred by the lamp if it has been running for 8 hours?
1.7 J
240 J
1.7 kJ
1.7 MJ
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Current flows through a resistor network made of three resistors, 
, 
and 
as shown.
What is the current in the resistor ?
0.3 A
0.5 A
0.7 A
1.0 A
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Kirchhoff’s first law is summarised by the statement:
The sum of currents entering a junction is always equal to the sum of currents leaving the junction
Kirchhoff’s first law is a consequence the conservation of which quantity?
Energy
Charge
Momentum
Baryon number
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A circuit consisting of two resistors divides the potential of the battery as shown:
What is the reading on the voltmeter?
0 V
0.33 V
0.66 V
1 V
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A circuit consisting of five identical resistors is shown:
Which of the following statements is false?
The potential difference between P and Q is equal to the potential difference between X and Y
The total resistance between X and Y is equal to the sum of the resistances between X and Y
The total resistance between P and Q is equal to the sum of the resistances along P and Q
There is less total resistance between P and Q than there is between X and Y
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Which of the following statements about resistance is true?
1 Ω is equivalent to 1 A V–1
The total resistance 
for two resistors in parallel and is given by = +
The combined resistance of two identical resistors in series is less than the combined resistance of two identical resistors in parallel
Resistors connected in series share the total potential difference available
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Two resistors are connected in parallel as shown:
What is the power generated in the 5 kΩ resistor?
10 kW
20 kW
30 kW
50 kW
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A cell of e.m.f. 2.0 V and negligible internal resistance is connected to a network of resistors as shown.
What is the current I?
0.25 A
0.33 A
0.50 A
1.5 A
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Two lamps are connected in series to a 250 V power supply. One lamp is rated 240 V, 60 W and the other is rated 10 V, 2.5 W.
Which statement most accurately describes what happens when the circuit is connected?
Both lamps light at less than their normal brightness
Both lamps light normally
Only the 60 W lamp lights
The 10 V lamp blows
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The diagram shows part of a current-carrying circuit. The ammeter has negligible resistance.
What is the reading on the ammeter?
0.7 A
1.3 A
1.5 A
1.7 A
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In the circuit shown, all the resistors are identical.
The reading on voltmeter V1 is 8.0 V and the reading on voltmeter V2 is 1.0 V. What are the readings on the other voltmeters?
| 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 |
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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
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A cell, two resistors of equal resistance and an ammeter are used to construct four circuits. The resistors are the only parts of the circuits that have resistance.
In which circuit will the ammeter show the greatest reading?
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The diagram shows a circuit with four voltmeter readings V, V1, V2 and V3.
Which equation relating the voltmeter readings must be true?
V = V1 + V2 + V3
V +V1 = V2 + V3
V3 = 2(V2)
V – V1 = V3
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When four identical resistors are connected as shown in diagram 1, the ammeter reads 1.0 A, and the voltmeter reads zero.
The resistors and meters are reconnected to the supply, as shown in diagram 2.
What are the meter readings in diagram 2?
| voltmeter reading / V | ammeter reading / A |
A | 0 | 1.0 |
B | 3.0 | 0.5 |
C | 3.0 | 1.0 |
D | 6.0 | 0 |
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The diagram shows currents I 1, I 2, I 3, I 4 and I 5 in different branches of a circuit.
Which one of the following is correct?
I 1 = I 2 + I 3
I 2 = I 1 + I 3
I 3 = I 4 + I 5
I 4 = I 5 + I 3
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In the circuit shown, all the resistors are identical and all the ammeters have negligible resistance.
The reading on ammeter A1 is 0.6 A.
What are the readings on the other ammeters?
| reading on ammeter A2 / A | reading on ammeter A3 / A | reading on ammeter A4 / A |
A | 1.0 | 0.3 | 0.1 |
B | 1.4 | 0.6 | 0.2 |
C | 1.8 | 0.9 | 0.3 |
D | 2.2 | 1.2 | 0.4 |
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A 12 V battery is in series with an ammeter, a 2 Ω fixed resistor and a 0 – 10 Ω variable resistor. High-resistance voltmeters P and Q are connected across the variable resistor and the fixed resistor, respectively, as shown.
The resistance of the variable resistor is changed from its maximum value to zero.
Which graph shows the variation with current of the voltmeter readings?
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The diagram shows a potential divider circuit which, by adjustment of the contact X, can be used to provide a variable potential difference between the terminals P and Q.
What range of potential difference is provided between P and Q?
5 V
10 V
20 V
25 V
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A potential divider consists of resistors of resistance R1 and R2 connected in series across a source of potential difference V0. The potential difference across R1 is Vout.
Which changes to R1 and R2 will increase the value of Vout?
| R1 | R2 |
A | doubled | doubled |
B | doubled | halved |
C | halved | doubled |
D | halved | halved |
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A network of resistors is set up as shown:
Between which two points does the minimum of resistance of the combination occur?
P and Q
R and S
Q and S
S and P
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Three identical resistors P, Q and R are connected in a circuit as shown:
The battery, of negligible internal resistance, supplies a total power of 15 W.
What is the power dissipated in resistor R?
2.5 W
5.0 W
7.5 W
8.0 W
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A light-dependent resistor R has a resistance of about 1 MΩ in the dark and about 1 kΩ when illuminated. It is connected in series with a 5 kΩ resistor to a 1.5 V cell of negligible internal resistance.
The light-dependent resistor is illuminated (in an otherwise dark room) by a flashing light.
Which graph best shows the variation with time t of potential difference V across R?
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A circuit is connected as shown in the diagram below:
What reading would a voltmeter measure if it was connected between P and Q?
0.50 V
0.75 V
1.0 V
1.5 V
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Three resistors are arranged in a circuit such that two measurements of input and output voltage are recorded, by swapping the arrangement of the cell and the voltmeter (which is assumed ideal), as shown:
The current supplied by the cell in arrangement 1 is 0.50 A.
Which row, A to D, gives the correct values of the resistances 
, 
and 
?
| R1 | R2 | R3 |
A | 10 Ω | 10 Ω | 15 Ω |
B | 6 Ω | 15 Ω | 10 Ω |
C | 6 Ω | 10 Ω | 15 Ω |
D | 15 Ω | 6 Ω | 10 Ω |
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Three identical, non-ideal voltmeters are connected as shown.
Each voltmeter has a finite resistance R which allows a small current to flow through them when connected to a source of emf, 
.
The I–V characteristic of the device D is unknown.
If 
= 2 V and 
= 3 V, what is the reading on 
?
1 V
2 V
4.5 V
5 V
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A student wishes to design a circuit which is sensitive to temperature changes in a room. They intend to connect a thermistor to a fixed resistor and a voltmeter, all across an input of 5 V, as shown:
Data about the resistance-temperature characteristics of the thermistor is shown below:
Temperature / ºC | Resistance Ω |
5.0 | 420 |
10 | 290 |
15 | 200 |
20 | 150 |
25 | 120 |
Which resistor, A to D, results in a circuit that is most sensitive to changes in room temperature?
50 kΩ
5 kΩ
500 Ω
50 Ω
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