Question

Name and state the rule to determine the direction of magnetic field around a straight current-carrying conductor.

Answer 1

 Maxwell’s right-hand thumb rule is used to determine the direction of magnetic field around a straight current-carrying conductor.

According to this rule, if we grasp a current-carrying wire in our right hand so that our thumb points in the direction of the current, the direction in which our fingers encircle the wire will give the direction of magnetic field lines around the wire.
When thumb points upwards, the curled fingers are anticlockwise. So, the direction of magnetic field lines is anticlockwise.
When thumb points downwards, the curled fingers are clockwise. So, the direction of magnetic field lines is clockwise.