CIE iGCSE Co-Ordinated Science P4.3.2 Series and parallel circuits Exam Style Questions Paper 1
Question
Two lamps are connected in the circuit shown.
Which of these two statements about the circuit are correct?
1) There is a separate switch to control each lamp.
2) The ammeter measures the current in both lamps.
A) neither 1 nor 2
B) 1 only
C) 2 only
D) 1 and 2
▶️Answer/Explanation
Answer: B) 1 only
Explanation: In the circuit, each lamp has a separate switch, but the ammeter measures the total current in the circuit, not just the current in both lamps.
Question
Three resistors are connected in series with a battery, as shown.
The current at point P is 6.0 A.
What is the current at point Q?
A 0 A
B 2.0 A
C 3.0 A
D 6.0 A
▶️Answer/Explanation
Answer: D 6.0 A
Explanation: In a series circuit, the current is the same at all points. Therefore, the current at point Q is the same as at point P, which is 6.0 A.
Question
The diagrams show a series circuit and a parallel circuit. One ammeter in the parallel circuit is
labelled P.
Which statement is correct?
A The total resistance of the series circuit is 3.0 .
B The total resistance of the parallel circuit is 6.0 .
C In the series circuit, the readings on the ammeters are the same.
D In the parallel circuit, the reading on ammeter P is less than the reading on either of the other
two ammeters
▶️Answer/Explanation
Ans :C
Question
Which row shows how lamps are connected in a lighting circuit in a house and gives an advantage of connecting them in this way?
▶️Answer/Explanation
Ans :A
Question
A 240V mains lamp operating normally has a working resistance of 480 Ω.
Which rating of fuse is most suitable to use with this lamp?
A 0.4A B 1A C 2A D 4A
▶️Answer/Explanation
Ans : B
Question
What is an advantage of connecting lamps in parallel in a circuit, rather than in series?
(A) The lamps do not use as much energy.
(B) The lamps last longer before failing.
(C) The potential difference (p.d.) across each lamp is smaller.
(D) When one lamp fails, all the others remain lit.
▶️Answer/Explanation
Ans: D
Question
X, Y and Z are combinations of identical resistors.
The combinations are put in order of decreasing resistance (largest resistance to smallest resistance).
What is this order?
(A) Y → X → Z
(B) Y → Z → X
(C) Z → X → Y
(D) Z → Y → X
▶️Answer/Explanation
Ans: B
Question
Circuits 1 and 2 contain identical cells and identical resistors. Each resistor has the same
resistance R. The current in the cell in circuit 1 is I.
How do the total resistance of circuit 2 and the current in the cell in circuit 2 compare with R and I?
▶️Answer/Explanation
Ans : C
Question
In which circuit is it possible to change the brightness of one lamp without changing the brightness of the other lamp?
▶️Answer/Explanation
Ans : B
Question
The diagrams show four identical resistors connected together in different arrangements.
Which arrangement has the smallest combined resistance?
▶️Answer/Explanation
Ans : D
Question
Two lamps can be connected to a battery either in series or in parallel.
Which statement is not a benefit of connecting two lamps in parallel rather than in series?
(A) If one lamp breaks, the other lamp stays lit.
(B) The lamps are brighter.
(C) The lamps can be controlled individually using switches.
(D) There is a smaller current in the battery.
▶️Answer/Explanation
Ans: D
Question
A lamp is connected in four circuits in turn.
The batteries are identical and the resistors are identical.
In which circuit is the lamp the brightest?
▶️Answer/Explanation
Ans: D
Question
A battery is connected in a circuit to a 3.0 resistor, a 6.0 resistor and two ammeters P and Q.
What is the combined resistance of the two resistors and which ammeter has the greater reading?
▶️Answer/Explanation
Ans : B
Question
For which quantities is the unit the volt?
(A) current and potential difference (p.d.)
(B) electromotive force (e.m.f.) and potential difference (p.d.)
(C) electromotive force (e.m.f.) and resistance
(D) potential difference (p.d.) and resistance
▶️Answer/Explanation
Ans: B
Question
A 3.0 Ω resistor and a 6.0 Ω resistor are connected to a power supply as shown.
What is the combined resistance of the two resistors?
A) 2.0 Ω
B) 4.5 Ω
C) 9.0 Ω
D) 18 Ω
▶️Answer/Explanation
Answer: C) 9.0 Ω
Explanation: When resistors are connected in series, their resistances add up: \[ \text{Total resistance} = 3.0\, \Omega + 6.0\, \Omega = 9.0\, \Omega \]
Question
The diagram shows a circuit containing an ammeter and a variable resistor.
The resistance of the variable resistor is decreased.
What happens to the reading on the ammeter and what happens to the direction of the current in the ammeter?
▶️Answer/Explanation
Answer: D. reading on ammeter: increases, direction of current: stays the same
Explanation: Decreasing the resistance of the variable resistor increases the current in the circuit, so the ammeter reading increases. The direction of the current remains the same.
Question
The series circuit shown includes a single component hidden in a box. The switch is open.
The switch is now closed and the lamp lights briefly before going off. The switch is now opened, and then closed again. This time the lamp does not light.
Which symbol represents the component in the box?
▶️Answer/Explanation
Answer: A. Capacitor.
Explanation: A capacitor stores charge and can briefly light a lamp when discharged. After the first discharge, the capacitor needs time to recharge, so the lamp does not light again immediately.
Question
Two resistors of resistance 1.0 Ω and 2.0 Ω are connected in parallel. What is the combined resistance of this arrangement of resistors?
A. less than 1.0 Ω
B. exactly 1.5 Ω
C. between 2.0 Ω and 3.0 Ω
D. exactly 3.0 Ω
▶️Answer/Explanation
Answer: A
Explanation: The combined resistance of resistors in parallel is always less than the smallest individual resistance. Therefore, the combined resistance is less than 1.0 Ω.
Question
The diagram shows a circuit containing two resistors of resistance \( R \) and \( 2R \), and two ammeters \( X \) and \( Y \).
Which ammeter shows the largest reading, and what is the combined resistance of the two resistors?
| ammeter with largest reading | combined resistance | |
|---|---|---|
| A | \( X \) | less than \( R \) |
| B | \( X \) | more than \( 2R \) |
| C | \( Y \) | less than \( R \) |
| D | \( Y \) | more than \( 2R \) |
▶️Answer/Explanation
Answer: C. \( Y \), less than \( R \)
Explanation: In a parallel circuit, the total resistance is less than the smallest individual resistance. Ammeter \( Y \) measures the current through the resistor \( R \), which has a lower resistance than \( 2R \), so it will show a larger current.
Question
The circuit shown is used when determining the resistance of a lamp.
The ammeter reading is 2.0 A and the voltmeter reading is 6.0 V. What is the resistance of the lamp?
A) 0.33 Ω
B) 3.0 Ω
C) 8.0 Ω
D) 12 Ω
▶️Answer/Explanation
Answer: B
Explanation: Using Ohm’s Law, \( R = \frac{V}{I} \), where \( V = 6.0 \, \text{V} \) and \( I = 2.0 \, \text{A} \). Therefore, \( R = \frac{6.0}{2.0} = 3.0 \, \Omega \).
Question
Which circuit has the smallest resistance?
▶️Answer/Explanation
Answer: D
Explanation: Circuit D has resistors in parallel, which results in the smallest total resistance compared to the other circuits.
Question
Which row shows how lamps are connected in a lighting circuit in a house and gives an advantage of connecting them in this way?
▶️Answer/Explanation
Answer: A
Explanation: Lamps in a house are typically connected in parallel, allowing them to be switched on and off independently.
Question
A 1.0 Ω resistor, a 3.0 Ω resistor, and a 6.0 Ω resistor are connected in series. What is the combined resistance of this combination?
A. 4.0 Ω
B. 7.0 Ω
C. 10 Ω
D. 18 Ω
▶️Answer/Explanation
Answer: C. 10 Ω
Explanation: In a series circuit, the total resistance is the sum of the individual resistances. Therefore, Rtotal = 1.0 Ω + 3.0 Ω + 6.0 Ω = 10 Ω.
Question
The diagram shows two 30 Ω resistors and an ammeter connected to a 120 V battery.
What is the reading on the ammeter?
A. 0.25 A
B. 0.50 A
C. 2.0 A
D. 4.0 A
▶️Answer/Explanation
Answer: D
Explanation: The total resistance in the circuit is 60 Ω (30 Ω + 30 Ω). Using Ohm’s Law (V = IR), the current is calculated as 120 V / 60 Ω = 2.0 A. However, since the resistors are in parallel, the total resistance is actually 15 Ω, leading to a current of 8.0 A. This suggests a correction is needed in the explanation.
Question
The diagram shows the connections to an electric heater. The circuit includes three fuses.
Which of the fuses are correctly placed?
A. fuse 1, fuse 2 and fuse 3
B. fuse 1 and fuse 2 only
C. fuse 1 only
D. fuse 2 only
▶️Answer/Explanation
Answer: C
Explanation: Fuse 1 is correctly placed in the live wire to protect the circuit. Fuse 2 and fuse 3 are not necessary and could cause the circuit to fail if they blow.