According to Maxwell’s hypothesis, a changing electric field gives rise to
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → a magnetic field
Maxwell found that Ampere’s circuital law was inconsistent for a charging capacitor. He added the displacement current \( i_d=\varepsilon_0\,d\Phi_E/dt \), which acts as a source of magnetic field just like a conduction current.
Option (1) an emf — Incorrect. An emf is induced by a changing magnetic flux (Faraday’s law). Maxwell’s hypothesis is the reverse effect, for a changing electric field.
Option (2) a conduction current — Incorrect. A conduction current is a flow of charges in a conductor. The changing electric field between capacitor plates gives a displacement current, through which no charge flows.
Option (3) a magnetic field — Correct. For logical consistency, a changing electric field must also produce a magnetic field, just as an electric current does. This is why time-varying electric and magnetic fields can sustain each other in an electromagnetic wave.
Option (4) an electric charge — Incorrect. Charges are the sources of electric fields. A changing field cannot create charge, since the total charge of an isolated system is conserved.
NCERT (2026-27):
Displacement Current – “We have seen in Chapter 4 that an electrical current produces a magnetic field around it. Maxwell showed that for logical consistency, a changing electric field must also produce a magnetic field. This effect is of great importance because it explains the existence of radio waves, gamma rays and visible light, as well as all other forms of electromagnetic waves.”