andrea96
- 10
- 1
if there is an uniform, infinitly extended,magnetic field that is changing with a law B(t), I can calculte the induced electric field using an arbitrary circle; then the induced circuitation on the circle is \epsilon _i=-\pi r^2 \frac{dB(t)}{dt}, and since the symmetry of the system ( infact each point on the circle isn't different from an other ) the electric field on the circle is \frac{r}{2} \frac{dB(t)}{dt}. But here there is a big problem: a different choise of r should not change the result ( again from the symmetry of the system ), but I have obteined an r-dependent result! I have a little explanation of this paradox, but I'd really like to know your answers... 
Thanks!

Thanks!
