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
1 markDifficulty: Medium
The core of an electromagnet is made of soft iron because soft iron:
- ais cheap
- bretains its magnetism after the current stops
- closes its magnetism as soon as the current stops
- dis a good conductor of electricity
Original Khojo Papers practice question — not from a past board paper.
Answer
loses its magnetism as soon as the current stops
No citable source has been recorded for this record. Treat it as practice material, not as fact.
Explanation
Low retentivity is exactly what an electromagnet needs, while a permanent magnet needs the opposite.
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