Answer:
(D) wrapping the copper wire around an iron nail or
(E) adding more loops to the wire
Explanation:
According to Ampere's Law, the magnetic field around a current-carrying wire is directly proportional to the strength of the current. In other words, increase in the current strength, increases the magnetic field.
Increasing the strength of a copper electromagnet, can also be done by wrapping wire that has an electrical current running through it around a nail. The more wire you wrap around the nail, the stronger your electromagnet will be.
Magnetic fields are produced by electric currents; a simple segment of current-carrying wire will generate around it, a circular magnetic field in accordance with the right hand rule. By adding more loops to a coil, you create an increasingly stronger magnetic field.
Therefore, wrapping the copper wire around an iron nail or adding more loops to the wire, will increase the strength of a copper electromagnet
