Zaymiey

⚛️ Physics  ·  Electromagnetic Waves  ·  NEET & JEE

In a plane electromagnetic wave travelling in vacuum, the ratio of the energy density stored in the electric field to that in the magnetic field is:

Answer: 1.

  • A 1
  • B c
  • C 1/c
  • D c<sup>2</sup>

Correct answer: A. 1

Explanation: In an EM wave the electric and magnetic energy densities are equal at every instant, so their ratio is 1.

Electromagnetic Wave: E ⊥ B ⊥ Direction of TravelpropagationE (electric field, vertical plane)B (magnetic field, horizontal plane, perpendicular to E)

In an electromagnetic wave, the oscillating electric field (E) and magnetic field (B) are perpendicular to each other and to the direction the wave travels - a purely transverse wave that needs no medium, unlike sound.

Concept context

Maxwell's equations, EM spectrum, properties, and applications of each band.

Read the full Electromagnetic Waves notes →