Question

State a law which determines the direction of magnetic field around a current carrying wire.

• A. Right hand thumb rule
• B. Left hand thumb rule
• C. Right hand index rule
• D. Left hand index rule

Answer 1

The correct option is A Right hand thumb rule

The Right hand thumb rule is used to determine the direction of magnetic field around a current carrying wire.
The rule states that when an electric current passes through a straight wire that is held by the right hand with the thumb pointing upwards and the fingers curling up the wire, the thumb points in the direction of the conventional current (from positive to negative), and the fingers point in the direction of the magnetic field.
Below figure represents the direction of current and magnetic field through a straight current carrying conductor.