Question

Testing Electromagnets



Students conduct two investigations using paper clips to observe the magnetic field produced by an electromagnet. The strength of the magnetic field is measured by the number of paper clips picked up by the electromagnet. The model shows the general setup for the electromagnet used in each investigation.



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In the first investigation, the students vary the number of coils wrapped around the steel nail. The data table shows the number of paper clips picked up by the electromagnet.


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In the second investigation, the students use the same number of coils around the nail but change the type of nail. They record the properties of each nail and the number of paper clips that the electromagnet picked up.


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The students create another electromagnet by wrapping four coils around a steel nail. The wire is connected to two batteries. What can the student do to increase the strength of the electromagnet's magnetic field?


use fewer batteries


use an aluminum nail


increase the number of coils in the wire


decrease the number of coils in the wire

Answer 1

increase the number of coils in the wire

More coils increase the magnetic field strength for the same current; using fewer batteries or an aluminum nail would weaken it, and decreasing coils would also weaken it.