Question

Braddy connected the lose wire to the battery and created an electromagnet. He picked up 45 thumb tacks with his electromagnet, though his goal was to pick up 50 thumb tacks. What could Braddy do to increase the strength of his electromagnet and pick up more thumbtacks?
A) Use fewer coils of wire.
B) Use a screw instead of a nail.
C) Use two batteries instead of one.
D) Replace the nail with a piece of steel.

Answer 1

Braddy could use two batteries instead of one.  One way he could increase the strength of his magnet is to increase the current and add a second battery. He could also add more coils of wire, not use fewer.

Answer 2

In order to increase the strength of  his electromagnet and pick up more thumbtacks Braddy should use two batteries instead of one. Using two batteries will increase the amount of current in the coils which will induce a higher electromagnetic field in the nail.
Another option would be to increase the number of coils of wire.