Question

A horizontal overhead power line carries a current of 90 A in east to west direction. What is the magnitude and direction of the magnetic field due to the current 1.5 m below the line?

Answer 1

given, power line carries a current, I = 90A.

point is located below the power line at a distance , r = 1.5m

we know, magnetic field at that point is given by the relation, B = $\frac{\mu_0i}{4\pi r}$ where $\mu_0$ is permeability of the space (vaccum) i.e., 4π × 10^-7 TmA-¹

B = (4π × 10^-7 × 90)/(4π × 1.5)

= 1.2 × 10^-5 T.

as it is mentioned that current is flowing from east to west and the point is located below the power line where we have to find direction of magnetic field.

according to Maxwell's right hand thumb rule, the direction of magnetic field towards the south.

Answer 2

Explanation:

Here your answer...

Magnetic field, B=2πrμoI

B=1.2×10−5T

Current flows from east to west, point is below the powerline.

Using right hand thumb rule, direction of B is southward.