Question

Two hikers are reading a compass under an overhead transmission line that is 5.30 m above the ground and carries a current of 790 A in a horizontal direction from north to south.

Find the direction of the magnetic field at a point on the ground directly under the conductor.

I already know the answer so I just need a full explanation why, I did the right-hand rule but its wrong so how?

Answer 1

Answer :

the direction of the magnetic field at a point on the ground directly under the conductor will be towards East.

According to Right hand thumb rule :  if your thumb of the right hand points along direction of current and if you grab the wire by curling your remaining fingers it will gives the direction of the magnetic field due to the current.

Here, if your thumb points in the direction of current in the wire (towards South) - and you grab the wire by curling your fingers. The fingers will point in the East. (directly under the conductor).

Note : You need to find the direction of magnetic field directly under the conductor - So, you must follow the direction of fingers when its under the wire.