Question

what happens to an iron bar when it is placed within the coils of a solenoid? it induces a current. it stops the current. it becomes a magnet. it loses its magnetism.

Explanation:

A solenoid carrying current produces a magnetic field. When an iron bar is placed within the coils of a solenoid, the magnetic field of the solenoid magnetizes the iron bar through the process of electromagnetic induction (specifically, magnetic induction). An iron bar is a ferromagnetic material, and in the magnetic field of the solenoid, its magnetic domains align, causing it to become a magnet (an electromagnet in this context, but the iron bar itself is magnetized). The first option is incorrect because the iron bar doesn't induce a current (the solenoid has the current, and the iron bar responds to the magnetic field). The second option is wrong as the iron bar doesn't stop the current. The fourth option is incorrect because the iron bar gains magnetism, not loses it.

Answer:

C. It becomes a magnet.