Out of the following, which one is not correct?

The correct answer is Option (2) → The electromagnetic wave can not be polarised

Electromagnetic waves are transverse: the electric and magnetic fields oscillate perpendicular to each other and to the direction of propagation. Only transverse waves can be polarised, so the statement that they cannot be polarised is the incorrect one.

Why the other options are incorrect

• Option (1) An accelerated charge is the source of electromagnetic waves — Correct statement. An oscillating (accelerated) charge produces time-varying electric and magnetic fields that radiate as a wave.

• Option (3) The electromagnetic waves can propagate through the space — Correct statement. They need no material medium, and travel through vacuum.

• Option (4) The electromagnetic waves propagate with the speed of light — Correct statement. In vacuum all of them travel at \( c = 1/\sqrt{\mu_0\varepsilon_0} \).

NCERT (2026-27):
Sources of Electromagnetic Waves – “… It is an important result of Maxwell’s theory that accelerated charges radiate electromagnetic waves.”

Nature of Electromagnetic Waves – “… They are self-sustaining oscillations of electric and magnetic fields in free space, or vacuum.”

Summary – “… Electromagnetic waves other than light also have the same velocity c in free space.”

Introduction – “… Finally in Section 10.7 we will discuss the phenomenon of polarisation which is based on the fact that the light waves are transverse electromagnetic waves.”