Final answer:
The distributed line parameter typically considered insignificant and thus often ignored in calculations is conductance. Examples like ceramic insulators and human resistance illustrate the significance of resistance in electrical circuits. Resistors are the elements that dissipate power, which is a key consideration for energy efficiency in electronic systems.
Step-by-step explanation:
The distributed line parameter that is normally significant but is usually ignored in calculations is D. Conductance. Conductance refers to the ability of a material to conduct electrical current and is the inverse of resistance. In the context of transmission lines, it represents the leakage of current through a dielectric or insulator separating the conductors. While resistance can also be a significant parameter in transmission line calculations, it is generally not ignored. However, conductance is commonly assumed to be negligible for practical calculations unless dealing with very high frequencies or other special conditions where dielectric losses are significant.
To understand the importance of resistance in a circuit, one can look at several examples. A ceramic insulator, like those used on power lines, can have resistances upwards of 10¹² ohms. Human resistance varies from about 10⁵ ohms for a dry person from hand-to-foot, to about 10³ ohms for the human heart. On the other hand, a large-diameter copper wire about a meter long might have a resistance as low as 10⁻⁵ ohms, and superconductors exhibit no resistance at room temperature (non-ohmic). Resistance is important as it affects the current through and the voltage across a resistor, with Ohm's Law relating the two by the equation V = IR.
When considering power dissipation within a circuit, the key elements that dissipate power are resistors, as illustrated by the question "Which circuit elements dissipate power?" with the correct answer being D. resistors. Capacitors and inductors do not dissipate power in an ideal scenario; they store energy in electric and magnetic fields, respectively. The notion of resistors dissipating power is important as it helps to understand energy efficiency and can impact the thermal management within electronic systems.