Question

betty made a simple electromagnet using just a battery and a wire. what could betty do to increase the strength of her electromagnet?
a. coil the wire around a nail.
b. coil the wire around a test tube.
c. coil the wire around a paper towel roll.
d. coil the wire around a toothbrush.

Explanation:

To increase the strength of an electromagnet, a ferromagnetic core (like a nail, which is made of iron) is used. Iron is a magnetic material that concentrates the magnetic field lines generated by the current - carrying wire, thus enhancing the magnet's strength. A test tube (usually glass or plastic, non - magnetic), a paper towel roll (paper, non - magnetic), and a toothbrush (usually plastic or nylon, non - magnetic) do not have ferromagnetic properties, so they won't enhance the electromagnet's strength like a nail will.

Answer:

A. Coil the wire around a nail.