The diagram shows an electromagnet made with copper wire, a steel nail,
and a 1.5 V battery. Which action could cause this electromagnet to be
stronger?
A. Replace the steel nail with a plastic straw.
B. Replace the battery with a 6 V battery.
C. Reduce the number of coils of wire wrapped around the nail.
D. Reverse the direction of the battery in the circuit.
Correct answer is B!