Chapter 20, Problem 3Q

To determine

The direction of magnetic field lines surrounding a straight wire carrying a current that is moving away from you.

Answer to Problem 3Q

Solution:

The direction of magnetic field lines surrounding a straight wire carrying a current that is moving away from you is in Clockwise direction.

Explanation of Solution

Introduction:

The magnetic field line direction in a current carrying straight wire is found using the right-hand grab rule. According to the right-hand grab rule, hold the wire in such a way that the thumb points in the direction of the current and the fingers will show the direction of the magnetic field lines.

Oersted found that the magnetic field lines surrounding a current carrying current are in circle form and close on themselves., as the field lines for a bar magnet are close on themselves.

Oersted found that the magnetic field lines surrounding a current carrying wire are closed curves. Similarly, the magnetic field lines of a bar magnet are also closed curves.

The magnetic field lines of a current carrying wire is as shown below:

From the diagram the magnetic field lines are in the clockwise direction, as the current is directed into the page.