Recent content by kartiksg

Energy of capacitor U = 1/2 CV^2. If voltage is constant and you bring the plates together, V stays put but C increases. So the energy increases. U = 1/2 Q^2/C. If u disconnect the power supply, Q stays put, but C increases. So U decreases. I think u can plug in and calculate the actual...

Direction of current is taken to be the direction in which positive charges move in a wire. We know that positive charges do not flow but the negative ones (electrons) do. These charges move in a direction opposite to the direction in which the positive charges were supposed to move. As an...

I was about to ask the same thing... I learned bout maxwell's four equations but I don't know how to relate the current produced or change in flux and its rate to the force exerted on the coil. If I knew the field strength of a magnet and parameters of a coils, can I calculate the velocity of...

I think it would not even be a novelty... it would come under those perpetual motion machines that violate the second law of thermodynamics... I think. Dont people always want something for nuttin :smile: Kartik

I have a doubt on the approach of GINIERE.. how can we continuously generate power from a magnet falling down a tunnel? After the inital moments, almost all of the magnetic field lines of the magnet is enclosed within the coils. Hence no more change ( or very little change) in magnetic flux...

Hi guys, I agree with arcnets. One must allow for the proper understanding of the principles of relativity in high school. One should not introduce it individually in itself, but must mould it with the concepts of electricity and Magnetism. In my post on Classical Electromagnetism, I was...

Hi, Thanks to all u ppl... I am finally beginning to get the hang of this... E field and B field by themselves arent Lorentz invariant but taken together, they are invariant. Force by itself is not invariant, but the four vector of force is. Thanks... Thanks a ton... I am finally...

Thanks a lot.. the site really helped... as for those weird looking equations... I guess Ill wait till I get to college and do partial derivatives before I try to get what it meant :wink: Again, Thanks a ton for the help Do write about why the forces need not be equivalent in...

Also, can u elaborate on how different observers will measure different charge densities for the stream of electrons? Can I also have an equation on how to describe the magnetic field of a moving electron? I have equations for fields of a current - Biot Savart Law.. but none for a single...

Thanks... I understood most of it... but I still didnt get the parallel electron part. You said that the magnetic field will exist in the frames where the electrons are in motion. So if in a frame, I see the electron moving with velocity v, I see 2 forces on the electrons 1. Coulombic force...

I still don't get how to apply v in the formula. Relative to what? How do I sense the movement relative to a field? Also, according to http://rognerud.com/physics/html/sec_1.html , it says u can interchange the fields... can someone gimme some feedback on that? Kartik

Hi, Im a little confused here... what exactly DOES happen when photons stike an interface between 2 media? People mentioned that it is absorbed and transmitted and hence the slow down. But why the particular direction change... and how can we explain Snell's law on the basis of collisions...

Hi, I would like to clarify some points on electromagnetism. Most (if not all) of my teachers say that moving charges create a magnetic field. I would just like to know... relative to what? If two electrons move parallel to each other with the same velocity, would they show any magnetic...