Final answer:
Hans Oersted's experiment showed that an electric current creates a magnetic field when he observed a compass needle deflecting near a current-carrying wire. This was substantiated by further experiments like Faraday's, demonstrating magnetic induction by producing a current through relative motion between magnet and coil.
Step-by-step explanation:
The investigation into the relationship between electricity and magnetism, notably carried out by Hans Oersted, demonstrated that a flowing electric current creates a magnetic field. Oersted's experiment involved passing an electric current through a wire which caused a nearby compass needle to deflect, proving that an electric current exerts a magnetic influence. This finding was groundbreaking as it linked two previously thought unrelated phenomena: electricity and magnetism. Subsequent experiments by other scientists, such as Michael Faraday and Joseph Henry, not only confirmed Oersted's discovery but also showed that magnetic fields could create currents, a principle known as magnetic induction.
These investigations collectively established the foundation for electromagnetic theory, leading to the understanding that changing magnetic fields can produce electric currents and vice versa. Faraday's further experiments, like moving a bar magnet through a wire coil, illustrated that current is induced in the wire due to the relative motion between the magnet and the coil, which aligns with the principle of magnetic induction. The reciprocal nature of this relationship is a profound example of nature's symmetry and underpins much of modern technology such as generators and electric motors.