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Perpendicular electric and magnetic field creates light or other electromagnetic waves. Is it a necessary property to have a perpendicular fields? If not what would happen when the fields are not perpendicular?

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A moving electric field, creates the perpendicular magnetic field. –  Optionparty Apr 14 '13 at 19:36
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@KaziarafatAhmed: Yes there is! In wave guides there modes of propagation. What we know as transverse electromagnetic field is just the TEM mode of a field. There are also the TE(transverse electric mode) with $B_z\neq 0$ and the TM(transverse Magnetic mode) with $E_Z\neq 0$ where $z$ is the direction of propagation! –  Thanos Apr 18 '13 at 12:33
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Just put a charge at rest in a magnetic field. The Coulomb field goes out in all directions, and will cross the magnetic field at every possible angle. Nothing special happens. –  Michael Brown Apr 18 '13 at 12:44
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please note that if $\vec{E} \vec{B}$ is not equal to $0$, i.e. fields are not perpendicular, then there always exist a reference frame where $\vec{E}$ is parallel to $\vec{B}$. In particular, this is the case of neutrino field. –  Murod Abdukhakimov Apr 18 '13 at 14:54
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@MurodAbdukhakimov: if ... fields are not perpendicular, then there always exist a reference frame where E is parallel to B Not true. The quantity $E\cdot B$ is a relativistic invariant. See en.wikipedia.org/wiki/… –  Ben Crowell Aug 17 '13 at 18:29
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Yes there is! In wave guides there modes of propagation. What we know as transverse electromagnetic field is just the $TEM$ mode of a field. There are also the $TE$(transverse electric mode) with $B_z≠0$ and the $TM$(transverse Magnetic mode) with $E_z≠0$ where $z$ is the direction of propagation!

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According to my understanding at physics, an electric field which is static cannot create any magnetic field.According to faraday for a magnetic field to exist there should be a varying electric filed(which varies over time).A simple example is battery connected to coil which is moved in and out near the galvanometer shows deflection(A galvanometer is device which detects magnetic filed by coupling magnetic filed near its vicinity to the coil inside and it internally has magnet which orients along the direction of earths's.The needle which is connected the coil coupling the magnetic field experiences a torque due to the EMF induced in it,and rests in the direction such that the earths magnetic field and the coupled magnetic are perpendicular to each other..hence the deflection of the galvanometer needle shows the stregth of magnetic field.

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According to faraday for a magnetic field to exist there should be a varying electric filed(which varies over time). No. This is only one of the two source terms for magnetic fields in Maxwell's equations. –  Ben Crowell Aug 17 '13 at 18:31
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