Identify the correct statement(s) among the following.
(A) In the propagation of electromagnetic waves the electric field and magnetic field vectors are perpendicular to each other and in same phase.
(B) In the propagation of electromagnetic waves the electric field and magnetic field vectors are perpendicular to each other and not in the same phase
(C) The electric and magnetic field vectors oscillate along the direction of propagation of em waves.
(D) Electromagnetic waves propagating in vacuum have momentum and energy.
Choose the correct answer from the options given below.
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → (A) and (D) only
In an electromagnetic wave, E and B are perpendicular to each other and to the direction of propagation and oscillate in the same phase.
(A) In the propagation of electromagnetic waves the electric field and magnetic field vectors are perpendicular to each other and in same phase. — Correct. E and B are in phase, with \( E_0 = cB_0 \).
(B) In the propagation of electromagnetic waves the electric field and magnetic field vectors are perpendicular to each other and not in the same phase — Incorrect. The two fields are in the same phase.
(C) The electric and magnetic field vectors oscillate along the direction of propagation of em waves. — Incorrect. Electromagnetic waves are transverse.
(D) Electromagnetic waves propagating in vacuum have momentum and energy. — Correct. They carry both; the momentum produces radiation pressure.
Note: Statements (A), (B) and (C) of this question are from the latest textbook (2026-27). Statement (D), that electromagnetic waves carry energy and momentum, is printed only in the pre-rationalised textbook (2022-23). It was removed from the latest book, but the characteristics of electromagnetic waves are still in the CUET 2026 syllabus, so do not skip it.
NCERT (2026-27):
Nature of Electromagnetic Waves – “It can be shown from Maxwell’s equations that electric and magnetic fields in an electromagnetic wave are perpendicular to each other, and to the direction of propagation.”
Nature of Electromagnetic Waves – “… The electric and magnetic fields Ex and By are perpendicular to each other, and to the direction z of propagation. We can write Ex and By as follows:
\( \displaystyle E_x = E_0 \sin(kz - \omega t) \qquad [8.7(a)] \)
\( \displaystyle B_y = B_0 \sin(kz - \omega t) \qquad [8.7(b)] \)”
NCERT (Pre-rationalised edition, 2022-23):
Nature of Electromagnetic Waves – “… Do electromagnetic waves carry energy and momentum like other waves? Yes, they do.”