Question

What is oersted experiment ? what is effect of a bar magnet on a compass needle​

Answer 1

Explanation:By setting up a compass through a wire carrying an electric current, Oersted showed that moving electrons can create a magnetic field. The magnetic field created by the current goes in circles around the wire.  Effect of Current on a Compass Needle - definition

Compass needle is a magnetic needle , so when placed still will align itself in north-south direction, if we bring a bar magnet near the compass the needle will deflect based on the property that like poles of two magnets repel each other.