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Physics · Electromagnetism
Strength of an electromagnet
A coil of insulated wire wrapped around an iron nail. When current flows, the nail behaves as a magnet. Vary the current and the number of turns, and count how many paperclips the electromagnet can pick up.
turns
current (A)
1.0 A
N×I = 60 A-turns · 4 paperclips
Results table
| N | I (A) | NI | clips |
|---|---|---|---|
| — | — | — | — |
Exam-style questions
1. Increasing the CURRENT in the coil makes the electromagnet:
2. Increasing the NUMBER OF TURNS (same current):
3. Why is the CORE made of SOFT iron?
4. If you REVERSE the current, what happens to the electromagnet?