Final answer:
The statement about high-voltage power lines being insulated is false; they are supported by insulating connectors but are not wrapped in insulating material. The concentric cylinders likely refer to a cylindrical capacitor, important in electromagnetic theory.
Step-by-step explanation:
The question is asking about the nature of high-voltage power lines and the configuration of cylinders in electromagnetic theory. The answer to the question regarding high-voltage wires is false. High-voltage power lines are indeed supported by insulating connectors to prevent the flow of electric currents into the towers. However, they are not wrapped in insulating material; instead, they are bare wires, primarily because at high altitudes and due to the considerable space around them, the air itself acts as an insulator.
In terms of the concentric cylinders, this question deals with the concept of a cylindrical capacitor in electrodynamics. When you have a solid cylindrical conductor and a concentric cylindrical shell, it can form a cylindrical capacitor. The potential difference between the two conductors can be calculated when they carry opposite charges, and appropriate dielectric materials can be used for insulation and to achieve specific capacitance values.