Maria makes an electromagnet shown in the figure below. The battery has a voltage of 6.0V, and she uses an iron nail. Which of the following would increase the strength of the magnetic field produced?
a
Reversing the direction of the current flow.
b
Changing the battery to a 3.0V battery.
c
Doubling the number of times the wire wraps around the nail.
d
Replacing the iron nail with one made of plastic.
c
Doubling the number of times the wire wraps around the nail. This would increase the number of coils in the electromagnet, increasing the strength of the magnetic field produced. The other options would either decrease the strength of the magnetic field or have no effect on it.