Question 1: Define a resistor and explain its role in an electrical circuit.

Answer: A resistor is a component that opposes the flow of electric current, used to control current levels and divide voltage in circuits.

Question 2: Describe the main difference between resistors connected in series and those connected in parallel.

Answer: Resistors in series are connected end-to-end, sharing the same current; in parallel, resistors are connected across the same two points, sharing the same voltage.

Question 3: Explain how the total resistance changes when resistors are added in series versus parallel.

Answer: In series, total resistance increases as resistors are added; in parallel, total resistance decreases because multiple paths reduce overall opposition.

Question 1: Calculate the equivalent resistance of three resistors of 4 Ω, 6 Ω, and 12 Ω connected in series. Use the formula R_eq = R1 + R2 + R3.

Answer: 22 Ω

Question 2: Determine the equivalent resistance of two resistors of 8 Ω and 16 Ω connected in parallel. Use the formula 1/R_eq = 1/R1 + 1/R2.

Answer: 5.33 Ω

Question 1: List three safety precautions to observe when setting up circuits with resistors in a laboratory setting.

Answer: Ensure power is turned off before connecting or modifying circuits, check resistor ratings to prevent overheating, and avoid touching live wires to prevent electric shocks.

Question 2: Identify at least two variables that could affect the resistance in a practical circuit experiment.

Answer: Resistor temperature (which can change resistance), and the quality or condition of the resistor contacts or connections.

Question 1: A circuit contains two resistors in parallel, R1 = 10 Ω and R2 = 20 Ω. If the total current supplied by the power source is 3 A, calculate the voltage across each resistor.

Answer: Voltage across R1 = 10 Ω × (3 A × (20 Ω / (10 Ω + 20 Ω))) = 10 Ω × 1 A = 10 V; Voltage across R2 = 20 Ω × (3 A × (10 Ω / (10 Ω + 20 Ω))) = 20 Ω × 1 A = 20 V.

Question 1: Explain why adding resistors in parallel decreases the total resistance, and provide a real-world example where parallel resistors are used.

Answer: Adding resistors in parallel provides multiple paths for current to flow, reducing overall opposition to current. A common example is household wiring, where appliances are connected in parallel to ensure each receives the full voltage and can operate independently.

Question 1: Identify a practical example of a device or system that utilises resistors in parallel, and explain the benefit of such configuration.

Answer: LED lighting systems often use resistors in parallel to ensure uniform brightness and to allow individual LEDs to operate independently without affecting others.