Electromagnets

Question

Electromagnets produce a magnetic field from an electrical current. Electromagnets can be found in the motors of everyday devices including cars, washing machines, refrigerators, and computers. The number of wire coils, type of nail, and voltage of the battery are a few factors that affect the strength of the magnetic field.

A group of students plans several investigations to test the factors affecting an electromagnetic field. First, they vary the number of times an insulated wire is wrapped around a steel nail. The ends of the wire are attached to each end of a 1.5 V battery to complete a simple circuit, as shown in the image.

The students record the maximum number of paper clips the magnet will lift for each trial.

Number of Coils Number of Paper Clips
10 3
20 7
30 9
40 12
Next, the students add a second battery and repeat the investigation.

They record the maximum number of paper clips the magnet will lift for each trial.

Number of Coils Number of Paper Clips
10 5
20 8
30 11
40 16
Then, they wrap insulated wire 25 times around different types of nails. The ends of the wire are attached to a single battery. The students record the properties of each type of nail and the maximum number of paper clips the magnet will lift for each trial.

Metal
Electrical Conductivity

Magnetic

(Yes/No)

Number of Paper Clips
Aluminum High conductivity No 0
Iron Medium conductivity Yes 15
Steel Low conductivity Yes 10
Multiple Select Question
An electromagnet has a single battery connected to an insulated wire that is wrapped 10 times around an iron nail. The electromagnet lifts 2 paper clips when tested.

What two actions could the students take to increase the number of paper clips the nail attracts?

A.
Use a longer nail

B.
Add another battery

C.
Reduce the number of coils

D.
Increase the number of coils

E.
Replace the iron nail with a steel nail

Answer 1

To increase the number of paper clips the nail attracts in the given scenario, the students could take the following two actions:

B. Add another battery - Increasing the voltage by adding another battery would increase the electrical current flowing through the wire, thereby strengthening the magnetic field produced by the electromagnet.

D. Increase the number of coils - Adding more coils of wire around the nail would also increase the strength of the magnetic field, allowing the electromagnet to lift more paper clips.

Thus, the correct choices are B and D.