Question

What initial observation in 1820 did Orsted make about the relationship between electricity and magnetism

Answer 1

The initial observation by Orsted was that there is a deflection of magnetized needle of compass when a current is switched on in a wire placed in neighborhood of compass.

later he conducted a experiment to find the relationship between current and field produced by it.

The he noted down the observation as follows:

• When we place compass needle in a plane perpendicular to the wire and there is no current in wire then needle is parallel to north-south direction.
• If the distance of compass from the wire is r and when current is switched on, needle deflects in such a way that it becomes parallel to a tangent at a circle of radius r about the wire.
• When the current is reversed then needle also reversed in North- South direction.