Question 1: Define electrical resistance and explain how it affects current flow in a circuit.

Answer: Electrical resistance is a measure of how much a material opposes the flow of electric current. Higher resistance reduces current flow in a circuit.

Question 2: List three factors that influence the resistance of a wire.

Answer: Material type, length of the wire, cross-sectional area, temperature.

Question 3: Calculate the resistance of a copper wire 50 meters long with a cross-sectional area of 1 mm², given the resistivity of copper is 1.68 × 10⁻⁸ Ω·m.

Answer: Resistance R = ρ × (L / A) = (1.68 × 10⁻⁸) × (50 / 1×10⁻⁶) = 0.84 Ω

Question 4: Which material generally offers the lowest resistance: copper, aluminium, or iron?

Answer: Copper

Question 5: Fill in the blank: Increasing the length of a wire ______ the resistance, while increasing its cross-sectional area ______ the resistance.

Answer: increases; decreases

Question 6: Describe a simple experiment to measure the resistance of a wire. Include the variables you would control and measure.

Answer: To measure resistance, set up a circuit with a power supply, ammeter, voltmeter, and the wire. Control variables include temperature and material type. Measure voltage across and current through the wire, then calculate resistance using R = V / I.

Question 7: Data from an experiment shows that a wire with a resistance of 2 Ω carries a current of 0.5 A. What is the voltage across the wire?

Answer: V = I × R = 0.5 × 2 = 1 V

Question 8: Explain why thicker wires have lower resistance compared to thinner wires of the same material and length.

Answer: Thicker wires have a larger cross-sectional area, which reduces resistance because more pathways are available for current to flow.

Question 9: Identify one safety precaution to consider when working with electrical circuits involving resistors.

Answer: Ensure the circuit is disconnected from the power supply before making any adjustments to prevent electric shock.

Question 10: In real-world applications, why is it important to manage resistance in electronic devices?

Answer: Managing resistance is crucial to control current flow, prevent overheating, improve efficiency, and ensure the device functions correctly and safely.