Aplane electromagnetic wave, with wavelength 6 m, travels in vacuum in the positive x direction with its electric vector e, of amplitude 214.6 v/m, directed along y axis. what is the frequency f of the wave? 250 mhz 100 mhz 50 mhz 105 mhz 25 mhz [2 points] (b) a plane electromagnetic wave, with wavelength 6 m, travels in vacuum in the positive x direction with its electric vector e, of amplitude 214.6 v/m, directed along y axis. what is the direction of the magnetic field associated with the wave? (i, j,k are the unit vectors corresponding to x, y and z directions) -j

a) For an EM wave traveling in a vacuum, this equation holds true:

c = fλ

c is the speed of light in a vacuum, f is the frequency, and λ is the wavelength.

Given values:

c = 3×10⁸m/s

λ = 6m

Plug in the values and solve for f:

3×10⁸ = f(6)

f = 50MHz

b) The direction of an EM wave's Poynting vector determines the direction of the wave's propagation.

S = 1/μ₀(E×B)

S is the Poynting vector, μ₀ is the magnetic constant, E is the electric field vector, and B is the magnetic field vector. Note that we are taking the cross product between E and B, not taking the product of two scalar quantities.

Since S depends on the cross product of E and B, you may use the right hand rule in the following way to determine the direction of B:

You can conclude that B must point along the z axis, so you can represent B with the k unit vector.

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