State the nature of the graph showing the change of magnetic field with the perpendicular distance from an infinitely long wire carrying a steady current.

Explanation

If current I flows through an infinitely long current distance r from the wire will be,
`B=(mu_(0)I)/(2pir)`
`:. B prop (1)/(r) [ :. and I` are constants]
So, the B-r graph will be a rectangular hyperbola [Fig. 1.91].