ENERGY IN TRANSFORMERS
3 marks · NormalDescribe two design features that help real transformers approach 100% efficiency. For each feature, briefly explain how it reduces energy losses.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
Must show: Thick copper wire (reduces resistance/heat losses), Soft iron core (better magnetic linkage/reduces eddy currents), Plastic coating on core (insulates and reduces eddy current losses)
Also accept: Laminating the core (reduces eddy currents)
Common mistakes: Stating the features without any explanation
Show mark scheme and worked solution
Marking points
B1 · 1 mark · Names first correct feature (e.g. thick copper wire, soft iron core, insulation, laminated core).
B2 · 1 mark · Explains how feature reduces losses (e.g. copper → less resistance/heat, iron/laminations → less eddy current).
B3 · 1 mark · Second feature with suitable explanation.
Worked solution
1. Thick copper wire: reduces resistance in coils, so less energy is wasted as heat. 2. Soft iron core with plastic/insulation: improves magnetic linkage between coils and reduces energy loss as heat from eddy currents.