Question 1: Define what a transformer is and explain its primary function in an electrical circuit.

Answer: A transformer is an electrical device that changes the voltage of an alternating current by electromagnetic induction, primarily to increase or decrease voltage levels in an electrical circuit.

Question 2: Describe how electromagnetic induction enables a transformer to change voltage levels.

Answer: Electromagnetic induction occurs when a changing magnetic flux through a coil induces an electromotive force (EMF) in a nearby coil, allowing energy transfer between the primary and secondary windings in a transformer.

Question 3: What is the function of the iron core in a transformer?

Answer: The iron core concentrates and guides the magnetic flux, increasing the efficiency of the electromagnetic induction process.

Question 1: A transformer has 500 turns in the primary coil and 50 turns in the secondary coil. If the primary voltage is 240 V, what is the voltage in the secondary coil? (Use the formula Vs/Vp = Ns/Np)

Answer: Vs = (Ns/Np) × Vp = (50/500) × 240 = 24 V

Question 2: A transformer delivers a secondary voltage of 12 V with a current of 2 A. If the input power is 48 W, what is the input current? (Assuming ideal transformer, use P = V × I)

Answer: Input power = Output power = 48 W; I_primary = P / Vp = 48 / 240 = 0.2 A

Question 1: List three safety precautions that should be observed when working with transformers in a high-voltage environment.

Answer: Ensure proper insulation, avoid contact with live parts, and use appropriate protective equipment.

Question 2: Identify three variables that can affect the efficiency of a transformer and briefly explain their impact.

Answer: Core losses (hysteresis and eddy currents), winding resistance (causing resistive heating), and magnetic leakage (reducing flux linkage) can decrease efficiency.

Question 1: A transformer with 1000 turns in the primary and 100 turns in the secondary is supplied with 240 V. The secondary current is measured at 2.4 A. Calculate the primary current assuming an ideal transformer. (Use the formula Ip / Is = Ns / Np)

Answer: Ip = (Ns/Np) × Is = (100/1000) × 2.4 = 0.24 A

Question 2: The efficiency of a transformer is found to be 95%, with a power loss of 2 kW. If the input power is 40 kW, what is the output power? Show your calculation.

Answer: Efficiency = (Power output / Power input) × 100; Power output = Efficiency × Power input = 0.95 × 40 kW = 38 kW

Question 1: Explain how step-down transformers are used in the distribution of electricity to homes.

Answer: Step-down transformers reduce high transmission voltages to safer, usable levels for household appliances, ensuring efficient and safe electrical supply.

Question 2: Identify a modern technology or industry that relies heavily on transformers and describe its significance.

Answer: The power grid relies on transformers for voltage regulation and distribution, which is essential for delivering reliable electricity over long distances.