Same chapter3 marksDifficulty: Medium
A transformer has 200 turns in its primary and 1000 turns in its secondary. If the primary is connected to a 220 V a.c. supply, find the secondary voltage and state the type of transformer.
Electromagnetism
2 marksDifficulty: Medium
Why does a transformer not work on a direct-current supply?
Original Khojo Papers practice question — not from a past board paper.
Answer
A transformer works by electromagnetic induction, which needs the magnetic flux through the secondary coil to change. A steady direct current produces a steady magnetic flux, so no e.m.f. is induced in the secondary and no output is obtained.
No citable source has been recorded for this record. Treat it as practice material, not as fact.
Explanation
Only at the instants of switching on and off would there be a momentary induced e.m.f.
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A transformer with more turns in the secondary than in the primary is a:
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