CIE iGCSE Co-Ordinated Science P4.3.2 Series and parallel circuits Exam Style Questions Paper 3
Question
(a) Fig. 6.1 shows an incomplete circuit diagram.
(i) Complete the circuit diagram in Fig. 6.1 by:
• adding an ammeter to measure the current in lamp A
• adding a voltmeter to measure the potential difference across lamp A.
(ii) Identify component X.
…………………………………………………………………………………………………………………….
(b) Lamp A has a resistance of 6.0Ω and lamp B has a resistance of 4.0Ω.
The current in lamp A is 1.2A.
(i) Calculate the potential difference across lamp A.
potential difference = ……………………………………………… V
(ii) Calculate the combined resistance of the two lamps connected in series.
resistance = ……………………………………………… Ω
(iii) The two lamps are now connected in parallel. Their combined resistance is different.
Identify from the list the combined resistance of the two lamps connected in parallel.
Explain your answer.
2.4Ω 4.0Ω 6.0Ω 10Ω 2 4Ω
combined resistance ……………………………………………………………………………………………
explanation …………………………………………………………………………………………………………
………………………………………………………………………………………………………………………….
(c) In lighting circuits in houses, lamps are connected in parallel.
State two advantages of using lamps connected in parallel rather than in series.
1 ………………………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………………………
2 ………………………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………………………
▶️Answer/Explanation
Ans: 6(a)(i) ammeter in series with lamp A completing the circuit ;
voltmeter across lamp A ;
both symbols correct ;
6(a)(ii) variable resistor ;
6(b)(i) p.d. = current × resistance (in any form) or 1.2 × 6.0 ;
= 7.2 (V) ;
6(b)(ii) 10.0 (Ω) ;
6(b)(iii) 2.4 (Ω) ;
resistance is less than the value of either individual resistance ;
6(c) any two from:
if one fails the other will still light ;
both lamps get full mains voltage ;
independent switching ;