A long,straight current-carrying wire runs from north to south.
A) A compass needle placed above the wire points with its N-pole toward the east. In what direction is the current flowing?
B) If a compass is put underneath the wire, which direction will the compass neddle point?
A) To determine the direction of the current flowing in the wire, we can use the Right Hand Rule.
1. Hold your right hand in a way that your thumb points upwards (towards the sky) and your fingers are wrapped around the wire with your palm facing the wire.
2. Align your thumb in the same direction as the compass needle pointing to the east above the wire.
3. In this scenario, your fingers will be curling in a counterclockwise direction. This indicates that the current is flowing from north to south in the wire.
B) To determine the direction the compass needle will point when placed underneath the wire, we can apply the same Right Hand Rule.
1. Hold your right hand in a way that your palm is facing the wire and your thumb points downwards (towards the ground).
2. Align your thumb in the same direction as the compass needle would be pointing underneath the wire.
3. In this case, your fingers will curl in a clockwise direction. Therefore, the compass needle will point in the opposite direction, which is towards the west.
So, to summarize:
A) The current is flowing from north to south.
B) The compass needle placed underneath the wire will point towards the west.