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An `EM` wave is propagating in a medium whith a velocity `vecv=vhati`. The instantaneous oscillating electric field of this of em wave is along `+y` axis. Then the direction of oscillating magnetic field of the `EM` wave will be alongA. `-y-direction`B. `+z-direction`C. `-z-`directionD. `-x-`direction |
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Answer» Correct Answer - B Here, velocity of EM wave, `v=vhat(i)` Instaneous oscillating electric field, `E=Ehat(j)` As we already know that, during the propogation of = EM waves through a medium oscillating electric and magnetic field vectors are mutually perpendicular to each other end to the direction of each other and to the direction of propogation of the wave `(ExxB)`. i.e. `ExxB=v rArr (Ehat(j) xx B = vhat(i)` ............(i) As we know that from vector algebra, `hat(j) xx hat(k)= hat(i)`..........(ii) ltbr. Comparing Eqs. (i) and (ii), we get `B= Bhat(k)`, Where B (say) be the magnitude of magnetic field. Thus, we can say that the direction of oscillating magnetic field of the em wave will be along +z direction. |
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