Question

15. Magnetic fields are created by
a. Nonmagnetic materials
b. Potential energy of molecules
c. Spinning neutrons
d. Moving electric charged in a current carrying wire.

Answer 1

(d) is correct

Any current (movement of electrical charge) will create a magnetic field. Certain materials are capable of realigning the angular momentum of their electrons, and iron is one of them. When the angular momentum of electrons gets aligned, an external magnetic field is created.

Answer 2

d. Moving electric charged in a current carrying wire.