Physics · Displacement current, electromagnetic waves and their characteristics, transverse nature of electromagnetic waves

When light propagates in vaccum there is an electric field and a magnetic field.

When light propagates in vaccum there is an electric field and a magnetic field. Which of the following is not true about these field?

  • A. They are constant in time
  • B. They have zero average value
  • C. They are perpendicular to the direction of propagation of light
  • D. They are mutually perpendicular

Step-by-step solution

In an electromagnetic wave propagating in vacuum, the electric and magnetic fields vary sinusoidally with time and space. They are not constant; they oscillate. The other options are true: fields have zero average value over a cycle, they are perpendicular to the direction of propagation, and they are mutually perpendicular.
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