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

Explanation

Here ` dx = 10 sin 30 cm `
`= 5 cm = 0.05 m`
`and du = 0.1xx 10^(-4)T-m`
Since `B = (du)/(dx)`
`= (0.1 xx 10^(-4)xx T - m)/(5 xx 10^(-2)m)`
` = 2 xx 10^(-4)T`
since B is porpendicular to equipotential surface gere it is angle `120^(@)`with (over) x- axis