A community of Physics Phans!

How do I start this problem? I'm not too sure where to begin, can I get some guidance?

A particular wire has a current of 10A.
A) How many electrons pass a fixed point every 5 seconds?
B)If a wire has a radius of 2 x 10^(-3) m and the electron drift speed is 2.63 x 10^(-5) m/s, determine the number density of electrons in the wire.

The teacher posts the answers for us, so the answer for
A) 3.125 x 10^(20) e^(-)
B) 1.89 x 10^(29) e^(-)/ m^3

Warning: is_dir() [function.is-dir]: open_basedir restriction in effect. File(/f1/content/ilovephysics/public/forum/uploads/) is not within the allowed path(s): (/f2/ilovephysics/:/nfsn/apps/php5/lib/php/:/nfsn/apps/php/lib/php/:/nfsn/content/content/nfsn/) in /f2/ilovephysics/public/forum/include/image_upload/image_upload.php on line 30

Last edited by ConfusedPhysicsStudent (2010-02-04 22:14:30)