For problems 11 and 12 A material with er = 2.25 is used as the insulating material in a lossless coaxial line with characteristic impedance of 50 ,,,. The radius of the inner conductor is 1.2 mm.
Problem  <10 points> What is the radius of the outer conductor in mm?
Problem  <10 points> What is the phase velocity of the line?
Problem  <5 points> A copper wire with circular cross-section and 1mm radius is 120 meters long. Find the AC resistance of this wire at 100 MHz. Copper has a conductivity of ,,,,,,,,
Problem  <10 points> Poynting vector of an electromagnetic wave is given as S y z = + 20 50 ˆ ˆ . Calculate the total power passing through a surface that is parallel to x-y plane and given as x y z = → = → = 0 2, 0 3, 0