Question

A current through a horizontal power line flows in east to west direction. What is the direction of magnetic field at a point directly below it and at a point directly above it?

• A. The direction of magnetic field at a point below the wire is from north to south. The direction of magnetic field at a point directly above the wire is from south to north.
• B. The direction of magnetic field at a point below the wire is from south to north. The direction of magnetic field at a point directly above the wire is from north to south.
• C. The direction of magnetic field at a point below the wire is from east to west . The direction of magnetic field at a point directly above the wire is from west to east.
• D. The direction of magnetic field at a point below the wire is from west to east. The direction of magnetic field at a point directly above the wire is from east to west

Answer 1

The correct option is A The direction of magnetic field at a point below the wire is from north to south. The direction of magnetic field at a point directly above the wire is from south to north.

The current is in the east-west direction. Applying the right-hand thumb rule, we get that the direction of magnetic field at a point below the wire is from north to south. The direction of magnetic field at a point directly above the wire is from south to north.