Physics · Electromagnetic Waves · NEET
Not particles and not a rope. What oscillates is the electric field (E) and the magnetic field (B) at each point in space. As the wave passes a point, E grows and shrinks and reverses, and B does the same in step with it. So an EM wave is a wave of changing fields, not a wave of moving matter.
No. Sound needs air or some material to travel because it is the vibration of matter. An EM wave is made of fields, and fields exist in vacuum. That is why sunlight reaches Earth through empty space. This is one of the most tested single-line facts for NEET.
Yes. Visible light is one small part of the electromagnetic spectrum. Radio waves, microwaves, infrared, visible light, ultraviolet, X-rays and gamma rays are all EM waves. They differ only in wavelength and frequency, but all travel in vacuum at the same speed c = 3 x 10^8 m/s.
No. EM waves carry energy and momentum, not charge. The wave has electric and magnetic fields, but the wave itself is neutral. A charge is only needed to produce the wave (an accelerating charge radiates), not to travel inside it.
An accelerating (or oscillating) electric charge produces an EM wave. When a charge speeds up, slows down or vibrates, it creates a changing electric field, which creates a changing magnetic field, which creates a changing electric field again, and so on. This chain lets the wave move outward on its own.
Try the real previous-year questions from this chapter — each with the answer and a full solution.
It is a wave of oscillating electric and magnetic fields that travel together through space at the speed of light, carrying energy without needing any medium.
All EM waves travel in vacuum at c = 3 x 10^8 m/s. This single speed is the same for radio waves, light, X-rays and gamma rays.
Yes. In a plane EM wave in vacuum, E and B reach their maximum and zero values at the same time and place; they oscillate in phase but are perpendicular to each other.
Maxwell predicted EM waves theoretically from his equations, and Hertz produced and detected them experimentally, confirming that light is an EM wave.
Almost every EM Waves question builds on this base idea: transverse nature, no medium, speed c, and E perpendicular B perpendicular to direction. Getting the basic picture right prevents many one-mark trap errors.
