Polyethylene with ?_r = 2.25 is used as the insulating material in a lossless coaxial line with a characteristic impedance of 50 Ω. The radius of the inner conductor is 1.2 mm.
(a) What is the radius of the outer conductor? (b) What is the phase velocity of the line?
Although the true numerical answers are provided bellow, please help me with the detailed solution.
a) b= 4.2 mm
b) u_p= 2*10^8 m/s