CIE iGCSE Co-Ordinated Science P4.5.6 The transformer Exam Style Questions Paper 1
Question
Electrical energy from a power station is transmitted over a large distance. A 100% efficient transformer is used near to the power station. This transformer reduces the amount of energy that is wasted thermally in the transmission cables.
How does the transformer reduce the amount of energy that is wasted?
A. It decreases the power transmitted so the current and the voltage are both larger.
B. It decreases the power transmitted so the current and the voltage are both smaller.
C. It increases the current so the voltage is smaller.
D. It increases the voltage so the current is smaller.
▶️Answer/Explanation
Answer: D
Explanation: Transformers are used to increase the voltage and decrease the current for long-distance transmission. This reduces the energy lost as heat in the transmission cables because power loss is proportional to the square of the current (P = I²R). Therefore, the correct answer is D.