i heard that a faraday cage is often used in shielding e.g. sensitive electrical equipment. I was just wondering, because, in http://socrates.berkeley.edu/~fajans/Teaching/cartoons/Shielding/TestChargeShielding_files/frame.htm it seems that the electric field is not zero at ALL times. i.e. there is an interval of time where an electric field does exist inside the cage, before the charges redistribute themselves. I was just wondering then, for the "shielding" application of the cage, that at that interval of time, couldnt the short-lived electric field still affect sensitive electrical eqipment housed inside? or is the above wrong, and there is another explanation that says that the electrical field is zero at ALL tiems. Thanks so much!