What Direction Does the Magnetic Field Oscillate in a Vertically Traveling Wave?

[lisamay44]

If an electric field wave oscillates north and south, and the wave is traveling straight up, then what direction does the magnetic field wave oscillate?

east and west
north and south
up and down
It does not oscillate; this situation is impossible.

I know that magnetic fields and electric fields travel perpendicular to each other. Do they travel perpendicular to each other on two dimensions (then the answer would be east and west) or do they travel perpendicular to each other on three dimensions (and then the answer would be up and down)? My initial reaction is that they travel perpendicular to each other on 3 dimensions (answer = up and down), but I am not sure.

 

[alphysicist]

Hi lisamay44,

You said that the electric and magnetic fields are pependicular to each other in an electromagnetic wave; now how are those fields related to the direction of travel of the wave?