Question

State the rule to determine the direction of a

1. magnetic field produced around a straight conductor-carrying current,
2. force experienced by a current-carrying straight conductor placed in a magnetic field which is perpendicular to it,
3. current induced in a coil due to its rotation in a magnetic field.

Answer 1

(i) Magnetic field produced around a straight conductor carrying current: The right-hand rule (or Maxwell's corkscrew rule) can be used to determine the direction of the magnetic field. Point your right thumb in the direction of the current flow (conventional current, from positive to negative), and the curl of your fingers around the conductor indicates the direction of the magnetic field.

(ii) Force experienced by a current-carrying straight conductor placed in a magnetic field which is perpendicular to it: Fleming's left-hand rule can be used to determine the direction of the force experienced. Point the index finger of your left hand in the direction of the magnetic field, the middle finger in the direction of the current, and the thumb will show the direction of the force acting on the conductor.

(iii) Current induced in a coil due to its rotation in a magnetic field: Fleming's right-hand rule describes the determination of the induced current's direction in a coil due to its rotation in a magnetic field. It involves aligning the thumb, forefinger, and middle finger of the right hand at right angles to each other. When the forefinger represents the direction of the magnetic field, the thumb indicates the motion of the conductor, and the middle finger shows the direction of the induced current in the conductor.