Question

FIGURE shows a bar magnet being pushed toward a conducting loop from below, along the axis of the loop.

a. What is the current direction in the loop? Explain.

b. Is there a magnetic force on the loop? If so, in which direction? Explain.

Hint: A current loop is a magnetic dipole.

c. Is there a force on the magnet? If so, in which direction?

Short answer

(a) The loop is now rotating clockwise.

(b) Yes, the magnetic force is directed upward.

(c) Yes, the force on a magnet travels downward.

Step-by-step solution

Introduction

There are two types of rectangular magnets that are shaped like bars: cylindrical bar magnets and rectangular bar magnets. Both types of bar magnets are capable of producing a powerful magnetic field. A rod magnet is a cylindrical bar magnet that is also known as a rod magnet.

Current direction in the loop (part a)

a.

As current increases, the magnetic field increases as well, resulting in current induction in the coil. The direction of induced current via the coil is anti-clockwise, according to Lenz law.

Magnetic force on the loop (part b)

b.

In a constant magnetic field, the resultant force on a loop is zero. A magnetic moment of magnitude IA and direction can be defined as shown. A current loop in a magnetic field that declines in magnitude to the right is in a magnetic field with a magnetic moment pointing to the left.

force on magnet (part c)

(a) From the top, clockwise. Some upward field of the north pole of the magnet causes the growing flux from the loop, so the induced magnetic field is downward.

(b) Yes, Upward . The produced descending field acts as a magnet with its north pole on the bottom, repelling the bar magnet.

(c) Yes, the trend is downward. The bar magnet is forced down by Newton's third law.