Extra exam question E9F03

WhyA coaxial cable's electrical length is longer than its physical length because electromagnetic waves move more slowly in coaxial cable than in air. A coaxial cable's electrical length ends up longer than its physical length because electromagnetic waves travel more slowly through the cable's dielectric material than they would through open air, so it takes a physically shorter length of cable to represent the same fraction of a wavelength that a longer run of open air would, answer D. Skin effect describes a different phenomenon (current crowding toward a conductor's surface), and waves don't move faster in coax than in air, they move slower, which is exactly why this electrical-versus-physical length discrepancy exists.