Karnataka Board PUCPUC Science 2nd PUC Class 12

Which of the Following Have Zero Average Value in a Plane Electromagnetic Wave? - Physics

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Short Note

Which of the following have zero average value in a plane electromagnetic wave?
(a) Electric field
(b) Magnetic field
(c) Electric energy
(d) Magnetic energy

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Solution

(a) Electric field
(b) Magnetic field

In a plane electromagnetic wave, the electric and the magnetic fields oscillate sinusoidally. For an electromagnetic wave propagating in the z-direction, the electric and magnetic fields are given by:
Ex = E0 sin (kz – ωt)
By = B0 sin (kz – ωt)
These are sinusoidal functions. Therefore, for a fixed value of z, the average value of the electric and magnetic fields are zero.

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Chapter 18: Electromagnetic Waves - MCQ [Page 339]

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HC Verma Class 11, Class 12 Concepts of Physics Vol. 2
Chapter 18 Electromagnetic Waves
MCQ | Q 4 | Page 339

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