The magnetic field induction near a straight current-carrying conductor of infinite length at a distance S from it will be

Derive an expression for the magnetic induction at a nearby point of a straight and long current-carrying conductor. Discuss the nature of the magnetic lines of induction.

The magnetic field induction at a point due to a current element is given by

The magnetic field due to a long straight wire carrying current varies directly as distance. (Correct the sentence)

The magnetic field at a distance 10 cm from a long straight current carrying conductor is 0.8T. The magnetic field at a distance 40 cm is