Question

Figure shows some of the equipotential surfaces of the magnetic scalar potential. Find the magnetic field B at a point in the region.

Answer 1

Given : 

Perpendicular distance, `dx = 10  sin 30^circ "cm" = 0.05  "m"` ,

Change in the potential, dV = `0.1 xx 10^-4  "T-m"`

We know that the relation between the potential and the field is given by 

`B = -(dV)/(dx)`

⇒ `B = -(0.1 xx 10^-4  "T-m")/(5 xx 10^-2  "m")`

⇒ `B = -2 xx 10^-4  "T"`

B is perpendicular to the equipotential surface. Here, it is at angle of 120° with the positive x-axis.