Question

AC current flows through a horizontal power line from east to west Direction What is the direction of magnetic field at a point directly below it and at a point directly above it

Answer 1

Heya friend!!
Rajdeep here...

Since AC current is flowing through the wire, the polarity above it and below it continuously changes 50 times a second (if the frequency is 50Hz).
So, below it, the magnetic needle speedily deflects. If the north pole is kept in the direction of flow of current, first it deflects towards the west and then east, again west, at a great speed (50 times a second).

Above the wire, first the needle deflects towards the east, then west, again east, 50 times a second.

Thanks!