Question

Select four of the following that would increase the magnetic field of an electromagnet.
A.

having a thicker wire

B.

no battery attached

C.

the number of wire coils

D.

having a magnet as a core

E.

the closeness of wire coils

F.

having a shorter wire

Answer 1

A, C, D, and E.

- A (thicker wire) — lower resistance → more current for a given battery → stronger field.
- C (more coils) — magnetic field increases with the number of turns.
- D (magnet as a core) — a ferromagnetic core concentrates and amplifies the field.
- E (closer/tightly wound coils) — coils packed together produce a stronger, more concentrated field.

(B no battery attached gives no current so no field; F shorter wire can be ambiguous — it reduces resistance but often means fewer turns, so it’s not a reliable way to increase the field.)