Who among the following suggested that a magnet must also exert an equal and opposite force on a current-carrying conductor?
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → André-Marie Ampère
Oersted had shown that a current-carrying conductor exerts a force on a magnet, deflecting a compass needle. The French scientist André-Marie Ampère (1775–1836) suggested that, by Newton’s third law, the magnet must also exert an equal and opposite force on the conductor. This force is seen when a current-carrying rod placed in a magnetic field is pushed sideways; its direction is given by Fleming’s left-hand rule.