High-frequency signals are often transmitted along a coaxial cable, such as the one shown in FIGURE CP30.86. For example, the cable TV hookup coming into your home is a coaxial cable. The signal is carried on a wire of radius r₁while the outer conductor of radius r₂is grounded. A soft, flexible insulating material fills the space between them, and an insulating plastic coating goes around the outside.

a. Find an expression for the inductance per meter of a coaxial cable. To do so, consider the flux through a rectangle of length l that spans the gap between the inner and outer conductors.b. Evaluate the inductance per meter of a cable having r₁ = 0.50 mm and r₂ = 3.0 mm.

Inner conductor radius i -Outer conductor FIGURE CP30.86