Q. 3

When light propagates in vacuum there is on electric field and a magnetic field. These fields
A. are constant in time

B. have zero average value

C. are perpendicular to the direction of propagation of light.

D. are mutually perpendicular

Answer :

The electric and magnetic fields that constitute light change continuously with time. Hence, option(A) is not true.

As these fields are sinusoidal waves, their average is zero. Hence, option(B) is correct.


The electric and magnetic fields are perpendicular to each other and to the direction of propagation. Hence, option(C) and (D) is correct.

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