Recent content by DaPi

dq/dt is the rate of increase of the charge on the upper plate and your diagram defines "i" as charge leaving it. So the equation relating the two is . . . . .

In only partial answer to the question, this puts it into a historical context, with some indications of the assumptions involved: http://webpages.uidaho.edu/~crepeau/ht2009-88060.pdf

Hmmmm when you close the switch does q increase or decrease?

Nicely put!

. . . and some will be reflected, n'est-ce pas?

I couldn't resist: http://www.smbc-comics.com/index.php?id=3701

is still causing a problem. There is nothing preventing you deriving a constant of the motion, multiplying it by m and proudly declaring this to be "THE ENERGY" The trouble comes when you want to show that this is the same as Energy as understood by everyone else. For this you'll have to...

Mohamed, you must realize that you are learning physics in an idealised world - sometimes called a model. In the real world conductors aren't spherical (they're bumpy due to the atoms making them up) and point charges don't exist. These are mathematical fictions that avoid having to deal with...

I hope the original problem gave some units for g!

Very very crudely (I hate to do this) it's because for a point off-centre there are more point charges on the sphere further away than there are closer - the effect balances out exactly when you add them all up. Surely any E&M textbook shows how to do the integration.

Pions from p-p collisions are more likely to come from the decay of high mass baryon states (deltas etc. etc.) than from the kind of process you've drawn.

A few thoughts: Yes, when you connect the human body to the chassis & the conducting elements, the "packaging" of the components could still be at lots of kV's. But: (1) the charge will leak away and the conduction path is shorter than the thickness of your shoes (I hope!) - I've no real idea...

Am I setting myself up to be shot down? Oh dear! It was a loooong time ago that I learned of Poynting's theorem in the integral form. We were given the health warning then that S being is an unwarranted assumption and only the integral over a closed surface was physically meaningful. In the...

Plank not using E = h * omega has probably spilt just as much ink.

Further to my previous post. This contains no physics! It's just a differential equation, which you manipulate and get a constant. It's relying on magic to equate this to E/m or whatever (does the "m" stand for magic?) The physics comes when this equation is applied to a physical situation...