Question

The magnetic effect of current is discovered by:
$A.$ John Ambrose Flemming
$B.$ Hans Christian Oersted
$C.$ Michael Faraday
$D.$ Andre-Marie Ampere

Answer 1

Hint: Here we will proceed by the meaning of magnetic effect of current and then we will try to demonstrate who discovered the magnetic effect of current.

Complete Step-by-Step solution:
Magnetic effect of current means that a current flowing in a wire produces a magnetic field round it. It concludes that a current flowing in a wire always gives rise to a magnetic field around it, the electric motor, telephone and radio, all utilize the magnetic effect of current.
The magnetic effect of electric current was discovered by Hans Christian Oersted in the year 1982. On 21 April 1820, Oersted published his discovery that a compass needle was deflected from magnetic north by a nearby electric current, confirming a direct relationship between electricity and magnetism.
Hans Christian Oersted made a surprising observation. As he was setting up his materials, he noticed a compass needle deflected away from magnetic north when the electric current from the battery he was using was switched on and off. This deflection convinced him that magnetic fields radiate from all sides of a wire carrying an electric current, just as light and heat do, and that it confirmed a direct relationship between electricity and magnetism.
The CGS unit of magnetic induction that is “Oersted” is named in honour of his contribution to the field of electromagnetism.
The correct option is B.

Note: Whenever we come up with this type of problem where we are asked to find out the discovery of a theory. Then we first write the history of the theory like in the question by observing the history of the magnetic field of current we find out how H.C. Oersted discovered it.