MYP Physics · 14 · multiple choice
Strengthen an electromagnet
Magnetism and electromagnetism · Original GioPhysics question with a detailed, mark-by-mark answer guide.
- Demand
- recall
- Marks
- 3
- Topics
- 2
- Answer
- Complete
A coil is wrapped around an iron nail and connected safely to a low-voltage supply. Which single change is most likely to make the electromagnet stronger?
- A
Reduce the number of turns on the nail
- B
Increase the current within the safe limit
- C
Replace the iron nail with a wooden stick
- D
Open the circuit
- a
Select and explain Select the best change and explain why it strengthens the field.
3 marks
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a
Select and explain Select the best change and explain why it strengthens the field.
Predict from the governing principle before looking for a matching option. Then reject alternatives by checking direction, units, limiting behaviour or the physical meaning of each statement.
- 1
Selects option B: increase the current through the coil while remaining within the safe limit.
- 2
States that a larger current produces a stronger magnetic field around the coil.
- 3
Recognises the safe-limit condition because excessive current can overheat the wire or supply.
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