2. The shielded pair consists of parallel conductors separated from each other, and surrounded by a solid dielectric. Which of the following materials acts as the shield?

A. Copper braid tubing

B. Polystyrene

C. Insulating spacers

D. Inert gases

3. The resistance of any conductor is never zero _________.

1. ohms
2. voltage
3. current
4. impedance

4. What substance allows the construction of a flexible cable whose dielectric losses, though higher than air, are still much lower than the losses that occur with other types of low-cost dielectrics?

A. Rubber

B. Polyethylene

C. Teflon

D. Pyrex