Electromagnetic waves are produced by

The correct answer is Option (3) → charge particle moving along a circular path

A charge at rest produces only an electric field, and a charge in uniform motion produces a steady current with a steady magnetic field. Electromagnetic waves are radiated only by an accelerated charge, whose oscillating or changing fields produce each other and travel outwards.

Option (1) charge at rest — Incorrect. A static charge has no changing fields, so it radiates nothing.

Option (2) charge in uniform motion — Incorrect. Uniform velocity means zero acceleration, so there is no radiation.

Option (3) charge particle moving along a circular path — Correct. Motion along a circle has a centripetal acceleration (the direction of velocity keeps changing), so the charge radiates.

Option (4) charge particle moving with velocity v along the direction of magnetic field — Incorrect. With \( \vec{v} \) along \( \vec{B} \) the magnetic force \( q\vec{v}\times\vec{B} \) is zero, so the charge moves with uniform velocity and does not radiate.

NCERT (2026-27):
Sources of Electromagnetic Waves – “How are electromagnetic waves produced? Neither stationary charges nor charges in uniform motion (steady currents) can be sources of electromagnetic waves. The former produces only electrostatic fields, while the latter produces magnetic fields that, however, do not vary with time. It is an important result of Maxwell’s theory that accelerated charges radiate electromagnetic waves.”