Exam-style question
Try this first
Describe how a transformer uses magnetic induction to transfer electrical energy between two circuits and explain why transformers are useful for power transmission.
Model answer
What a good answer should say
- A transformer transfers electrical energy between two windings by linking them through a common magnetic core.
- When an alternating current flows through the primary winding, it creates a changing magnetic flux that induces an emf in the secondary winding via Faraday's law.
- The ratio of induced emf to primary emf is proportional to the turns ratio, allowing voltage to be stepped up or down.
- Transformers are useful for power transmission because stepping up voltage reduces current for a given power, thereby reducing resistive losses in transmission lines.
Explanation
Why this works
The answer shows knowledge of transformer operation, the role of magnetic induction, Faraday's law, and the practical benefit of voltage transformation for efficient power transmission. It tests the student's ability to connect the induction principle to real-world applications.
Common mistake
No common mistake is linked to this question yet.