Question

What is the velocity factor of a coaxial cable having an insulator with dielectric constant 2.1?

(a) 0.69

(b) 0.54

(c) 0.32

(d) 0.45

I have been asked this question in a job interview.

Enquiry is from Transmission Line Basics in chapter Transmission Lines of Avionics

Answer 1

Correct option is (a) 0.69

The explanation: The velocity factor in a line can be computed with the expression

Where ε is the dielectric constant of the insulating material.