I obtained an HDMI cable form Amazon to connect my DVD player to the TV, and recognized that the shorter the cable, the better it will conduct electricity.

In fact, this applies to any electrical wire. Consider a simple electrical law, Ohm’s law, or the current delivered times the resistance to current equals the voltage. Voltage is the electrical potential energy difference between either end, so in this case, given voltage is constant, the more it resists electricity the less current it will bring.

Resistance is based on three factors: the area of the wire, its length, and a intrinsic property of the conductor used, known as the resistivity. The resistance increases with resistivity and length, but decreases (i.e., conducts better) with area. Assuming the resistivity and area are constant (at least when choosing among cables of a particular brand, etc.) one should observe the length of the cable should be as short as possible to optimize quality for any electrical need. (That is, if you have a choice.)

As long as it will stretch the distance you need, in short, grab the shortest cable possible!