What is the nature of magnitude lines of force due to current in a straight conductor?

Draw the pattern of magnetic field lines around a current carrying straight conductor.How does the strength of magnetic field produce change with an increase in current in a conductor?

Two long straight parallel conductors 'a' and 'b', carrying steady currents Ia and Ib are separated by a distance d. Write the magnitude and direction of the magnetic field produced by the conductor 'a' at the points along the conductor 'b'.If the currents are flowing in the same direction, what is the nature and magnitude of the force between the two conductors ? F_(BA) = (mu_0I_A I_B L)/(2pid)

The self-inductance of a straight conductor is