Recent content by The_Cat

Well, the accumulation of energy in the charging of a capacitor is of course neatly demonstrated by the poynting vector pointing inward. But lightning is a breakdown of the clouds/earth capacitor, where the stored charge shoots from one half to the other. And if my...

Oh, I thought you were referring to the Stokes equation of hydrodynamics. And when talking about water, it is usually assumed that it is incompressable, or div(v)=0, if I remember correctly.

from stokes theorem it follows that there can be no net accumalation of water within a closed surface. What it means is that density of water cannot be changed which implies that water can never be compressed however much you try. Isn't that an assumption used to derive stokes' equation?

My first intuition would say that if you would try to charge a capacitor with a bolt of lightning, you'd just melt your capacitor. Remember, we're talking about a voltage high enough to discharge through at least tens of meters of air, so I highly doubt there is a man-made capacitor that can...

There is no loss of energy, only increase of entropy.

Indeed, the electrical field doesn't dissapear. It will become weaker along the line of motion, and stronger in the plane perpendicular to it if you get to high enough velocities, but it won't go away.

I know the question sounds ridiculously simple, but I haven't been able to form an answer. What is charge? Why do particles have an electrical charge and where does it come from? Is it just a basic property of particles or is there a mechanism? For your information: I'm a third year undergrad...