Which of the following statements for a solenoid is not true? a) your right-hand thumb must be pointed in the direction of the south pole. b) the fingers of your right hand are curled in the direction of the electric current c) to determine the magnetic field you grasp the coil in your right hand. d) a solenoid consists of a coiled conductor

(a) Your right-hand thumb must be pointed in the direction of the south pole.

Explanation:

A solenoid is a coil of insulated copper wire which behaves like a magnet when an electric current passes through it and it loses its magnetic behaviour just after the current flow stops.

Since it behaves a magnet, the magnetic poles must be determined. In order to determine the magnetic pole, we put the coil in our right hand, curl our four fingers in the direction of current flow and then the direction in which our thumb points is the north pole. This is known as the Right-hand rule.

From the above discussion, option (a) does not keep pace with the statement of right-hand rule.

Hence, option (a) is not true.