Q.39

Expert-verified
Found in: Page 832

### Physics for Scientists and Engineers: A Strategic Approach with Modern Physics

Book edition 4th
Author(s) Randall D. Knight
Pages 1240 pages
ISBN 9780133942651

# A small bar magnet experiences a torque when the axis of the magnet is at to a magnetic field. What is the magnitude of its magnetic dipole moment?

The magnitude of its magnetic dipole moment is .

See the step by step solution

## Step  1 : Given Information

We need to find the magnitude of its magnetic dipole moment.

## Step 2 : Simplify

The torque represents the magnitude of the force multiplied by the distance between the axis and the line of the action. A current loop inside a magnetic fields experiences a torque that is exerted by the magnetic force and the loop starts to rotate. For a square loop with side , its torque is given as:

where represents the magnetic dipole moment of the loop, is the current in the loop and is the angle between the magnetic field and the magnetic dipole moment of the loop.

When the dipole moment is parallel to the magnetic field, the torque is zero and it is maximum when the dipole moment is perpendicular to the magnetic field. Our target is to find Therefore we rearrange equation (1) for to be in the form of :

## Step 3: Calculation

Now, We plug the values for into equation (2) to get :