Draw the pattern of magnetic field lines associated with a current-carrying straight conductor. State how the magnetic field produced changes:
$(i)$ with an increase in current in the conductor,and
$(ii)$ with an increase in the distance from the conductor.

(N/A) The pattern of magnetic field lines around a current-carrying straight conductor consists of concentric circles centered on the conductor.
$(i)$ The strength of the magnetic field is directly proportional to the current flowing through the conductor. Therefore,the magnetic field increases with an increase in the current.
$(ii)$ The strength of the magnetic field is inversely proportional to the distance from the conductor. Therefore,the magnetic field decreases as the distance from the conductor increases.