# A conducting loop is halfway into a magnetic field. Suppose the magnetic field begins to increase...

## Question:

A conducting loop is halfway into a magnetic field. Suppose the magnetic field begins to increase rapidly in strength. What happens to the loop?

a) The loop is pulled to the left into the magnetic field.

b) The loop is pushed to the right, out of the magnetic field.

c) The loop is pushed upward, toward the top of the page.

d) The loop is pushed downward, toward the bottom of the page.

## Electromagnetic induction

According to the Faraday-Lenz law (law of electromagnetic induction), when the magnetic field flux that passes through a conductive loop varies, an electromotive force will appear in the loop whose effects are contrary to the cause that originates it.

Suppose that initially the external magnetic field was constant, so that no current was flowing in the loop. When the intensity of the external magnetic field increases sharply, an induced electric current will appear on the loop that will generate a magnetic field. Inside the loop the direction of the induced magnetic field is contrary to the direction of the external magnetic field. Therefore, it is as if we had two identical magnetic poles inside each other. As equal poles repel, then the loop will move to the right outside the external magnetic field (option B).