The displacement current made the laws of electricity and magnetism more symmetrical. These laws are still not perfectly symmetrical because
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → no sources of magnetic field (magnetic monopoles) like electric charges are known
Faraday’s law says that a changing magnetic field gives rise to an electric field. The displacement current gives the reverse link. An electric field that changes with time gives rise to a magnetic field.
Option (1) the displacement current has physical effects different from those of the conduction current — Incorrect. The displacement current has the same physical effects as the conduction current. It is a source of magnetic field in the same way.
Option (2) no sources of magnetic field (magnetic monopoles) like electric charges are known — Correct. Electric charges are sources of electric field. No such sources of magnetic field have been found, so the two sets of laws still differ.
Option (3) the displacement current is zero when the electric field does not change with time — Incorrect. This is true, but it does not break the symmetry. In the same way, a magnetic field that does not change with time gives no induced electric field.
Option (4) a magnetic field that changes with time does not produce an electric field — Incorrect. This goes against Faraday’s law. A magnetic field that changes with time does give rise to an electric field.
NCERT (2026-27):
Displacement Current – “They are still not perfectly symmetrical; there are no known sources of magnetic field (magnetic monopoles) analogous to electric charges which are sources of electric field.”