Identify the 19th century scientist who played a crucial role in understanding electromagnetism
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Hans Christian Oersted
Note: The given answer is as per the official NTA Answer Key. However, the question has more than one correct answer, i.e. Option (2), Option (3) and Option (4), as explained below.
Electromagnetism is the study of the link between electricity and magnetism. Three of the scientists named in the options shaped it in the 19th century:
Option (2) Hans Christian Oersted — in 1820 he noticed that a compass needle near a wire turned whenever a current flowed in it, showing that an electric current produces a magnetic field; this began the study of electromagnetism. This is the answer given by NTA.
Option (3) Michael Faraday — in 1831 he discovered electromagnetic induction: a changing magnetic field produces a current in a nearby coil, the principle of the generator and the transformer.
Option (4) James Clerk Maxwell — in the 1860s he set out the equations that unite electricity and magnetism and showed that light is an electromagnetic wave.
Georg Simon Ohm is known for Ohm’s law (1827) on current, voltage and resistance in a circuit, not for a discovery about magnetism.
Tip for students: When a question has more than one possible answer, mark the one you worked out yourself. If NTA’s answer key gives a different answer, challenge it when NTA opens the window for challenges.