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Question
An electromagnetic wave travels in vacuum along z direction: `E = ( E_1hati + E_2hatj ) cos (kz - ωt)`. Choose the correct options from the following:
- The associated magnetic field is given as `B = 1/c(E_1hati - E_2hatj) cos (kz - ωt)`.
- The associated magnetic field is given as `B = 1/c(E_1hati - E_2hatj) sin (kz - ωt)`.
- The given electromagnetic field is circularly polarised.
- The given electromagnetic wave is plane polarised.
Options
a and b
b and c
c and d
a and d
Solution
a and d
Explanation:
We are given that the electric field vector of an electromagnetic wave travels in a vacuum along z-direction as `vecE = (E_2hati + E_2hatj) cos (kz - ωt)`
The magnetic of the electric and the magnetic fields in an electromagnetic wave are related as `B_0 = E_0/c`
`vecB = vecE/c = (E_1hati + E_2hatj)/c cos (kz - ωt)`
Also, `vecE` and `vecB` are perpendicular to each other and the propagation of electromagnetic wave is perpendicular to `vecE` as well as `vecB`, so the given electromagnetic wave is plane polarized.
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