CIE iGCSE Co-Ordinated Science P4.2.4 Resistance Exam Style Questions Paper 1
Question
Four resistors are connected into circuits. The current in each resistor and the
potential difference (p.d.) across each resistor are shown.
Which resistor has a resistance of 2.0?
▶️Answer/Explanation
Ans: D
Question
There is a current of 4.0A in a resistor and a potential difference (p.d.) of 12V across it.
What is the resistance of the resistor?
(A) 0.33Ω (B) 3.0Ω (C) 8.0Ω (D) 48Ω
▶Answer/Explanation
Ans : B
Question
A resistor R is connected to a 12V battery and an ammeter as shown.
The ammeter reads 6.0A.
What is the resistance of resistor R?
A. 0.50Ω
B. 2.0Ω
C. 18Ω
D. 72Ω
▶️Answer/Explanation
Answer: B. 2.0Ω.
Explanation: Using Ohm’s Law, \( V = IR \), the resistance \( R = V / I = 12V / 6.0A = 2.0Ω \).
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: Resistance is calculated using Ohm’s Law: \( R = V / I \). Substituting the given values: \( R = 6.0 \, \text{V} / 2.0 \, \text{A} = 3.0 \, \Omega \).
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. 3.0 Ω
Explanation: Resistance is calculated using Ohm’s Law: \( R = \frac{V}{I} \). Substituting the values, \( R = \frac{6.0 \, \text{V}}{2.0 \, \text{A}} = 3.0 \, \Omega \).
Question
There is a current of 4.0 A in a resistor and a potential difference (p.d.) of 12 V across it. What is the resistance of the resistor?
A. 0.33 Ω
B. 3.0 Ω
C. 8.0 Ω
D. 48 Ω
▶️Answer/Explanation
Answer: B. 3.0 Ω
Explanation: Using Ohm’s Law, resistance (R) is calculated as R = V/I, where V is the potential difference and I is the current. Therefore, R = 12 V / 4.0 A = 3.0 Ω.
Question
A student connects a length of metal resistance wire to a battery.
The student wishes to increase the current in the resistance wire. Which change does this?
A. connecting a second wire in series with the first wire
B. heating the wire
C. making the wire shorter
D. making the wire thinner
▶️Answer/Explanation
Answer: C
Explanation: Making the wire shorter reduces its resistance, which increases the current in the circuit according to Ohm’s Law (V = IR). A shorter wire has less resistance, allowing more current to flow.