I am having a hard time picturing waves, the image that comes to mind is a bobbing device submerged in still water which generates pulses in all directions (similarly in air). Then how can a wave be two dimensional? The classic image of an electromagnetic wave is a 3D wave function, x-y represent the electrical component, z-x represents the magnetic component. But this is a wave function, so its just a plot, and that is not how I should picture it (or is it?). So in real life, if I have a source of EMR in space, I can imagine concentric spheres of Electrical fields, but what about the magnetic fields? How will they be perpendicular to a sphere of electric fields? Can someone help me picture EMR? Thanks! (apologies in advance for the noobish language, I am an absolute beginner to physics)
Ok I think I understand your question.
So you're talking about how the electromagnetic waves are always perpendicular to each other, but now, what if we have a spherical electromagnetic wave?
Ok there's a few problem to sort out. First off, electromagnetic waves always travel in a straight line (ignoring effects like general relativity, diffraction (and other scattering processes), etc.). You might already know that, but when bringing up a spherical wave you are probably getting confused. What is this spherical wave and how is it formed? Well, this EM source sounds a lot like the bobbing device in water...at least from what you're describing...causing an outward flux of EM waves in a spherical manner. This actually is just a bunch of EM waves going in a single direction. The photons within the EM waves are traveling in straight lines still. The "spherical" wave is just a bunch of regular EM waves combined together. That explains why the intensity diminishes the farther the radius from your source is.
So instead of picturing waves as 3D, picture them as a bunch of 2D waves strung together. Physics' current understanding is that photons are point particles, so if a point moves in a line (well a curved line I suppose), it is making a 2D shape. The magnetic wave is orthogonal to the electric wave, so the EM wave actually spans 3 dimensions.
So to now answer your question, each part of the EM wave moves in 2 dimensions and you can think of it as a sine wave or a cosine wave plot. Both of them together spans 3 dimensions, but each individual part just spans 2 dimensions.