CIE iGCSE Co-Ordinated Science P4.3.1 Circuit diagrams and circuit components Exam Style Questions Paper 1
Question
In which circuit can the brightness of the lamp be varied continuously?
▶️Answer/Explanation
Answer: A
Explanation: A variable resistor (rheostat) allows the current in the circuit to be adjusted, which in turn varies the brightness of the lamp continuously.
Question
Which circuit can be used to take measurements to determine the resistance of resistor R?
▶️Answer/Explanation
Answer: D
Explanation: To measure resistance, the voltmeter must be connected in parallel across the resistor to measure the voltage, and the ammeter must be connected in series to measure the current. Ohm’s Law (R = V/I) can then be used to calculate the resistance.
Question
Which circuit shows an ammeter that measures the current in the lamp and a voltmeter that measures the potential difference (p.d.) across the lamp?
▶️Answer/Explanation
Answer: C
Explanation: In Circuit C, the ammeter is correctly placed in series with the lamp to measure the current, and the voltmeter is correctly placed in parallel with the lamp to measure the potential difference across it.
Question
What is represented by the circuit symbol shown?
A fixed resistor
B fuse
C switch
D variable resistor
▶️Answer/Explanation
Answer: D variable resistor
Explanation: The symbol shown represents a variable resistor, which is a resistor whose resistance can be adjusted.