Immediately outside a very long, cylindrical wire of radius R1=0.6mm, the electric field is 50 kV/m directed towards the wire's surface. The wire is in air.
What is the charge per unit along length the wire? (take care with sign)
What is the field at R2=3.0mm? (i.e. 2.4mm from the wire's surface)
A hollow cylindrical metal tube with inner radius 3.0mm is now placed around the wire, to form a coaxial cable, what will be the charge per unit length on the inner surface of this tube? Explain.
Really not too sure,
The Attempt at a Solution
even just a headstart would be much appreciated if anybody knows how to solve these.