Nature Of Em Waves

As stated in NCERT Class 12, Chapter 8 (Electromagnetic Waves), an electromagnetic wave is a transverse wave in which the electric field E and the magnetic field B oscillate in phase but in planes at right angles to each other. Furthermore, both fields are perpendicular to the direction of wave propagation, given by the direction of E × B. Thus E, B, and the propagation vector form a mutually perpendicular right-handed set. This transverse, mutually orthogonal structure is what allows electromagnetic waves to be polarised. The option stating all three are parallel is wrong because parallel fields would not sustain a self-propagating wave. The claim that E and B are parallel to each other contradicts Maxwell's equations, which require them to be perpendicular. The option placing the electric field along the propagation direction is incorrect because a transverse wave has no field component along its travel direction. A structural check using the right-hand rule for E × B confirms the mutually perpendicular arrangement, validating the answer.