Extra exam question E9F08

WhyCompared to solid dielectric coaxial cable, foam dielectric coaxial cable has a lower safe maximum operating voltage, lower loss per unit length, and a higher velocity factor. Compared to solid dielectric coax with otherwise identical parameters, foam dielectric coax has a lower safe maximum operating voltage, lower loss per unit length, and a higher velocity factor, all consequences of foam's dielectric being mostly air pockets rather than solid plastic, answer D. Since foam dielectric genuinely differs from solid dielectric in all three of these ways, no single one alone is the complete answer.