Final answer:
The statement about physical and logical topologies differing only in a bus topology is false; they can differ in other layouts as well. High-voltage wires on towers are not insulated, and wood can conduct lightning due to its potential to be ionized. Refraction is indeed useful for transmitting signals in fiber optic cables.
Step-by-step explanation:
The statement "The only case in which a physical topology may differ from a logical one is when a physical bus topology is used" is false. Physical and logical topologies can differ in various network configurations, not just the bus topology. A physical topology refers to the actual layout of network cables and devices, whereas a logical topology signifies the paths that the data takes within the network. For example, in a physically star-wired ring topology, each device is connected to a central hub (physical star), but data travels in a ring-like pattern (logical ring).
In circuit diagrams, it is also false that we can assume that the voltage is the same at every point in a given wire. There might be voltage drops across components, meaning different points in the wire can have different voltages.
The high-voltage wires that you see connected to tall metal-frame towers are indeed held aloft by insulating connectors. However, it is false that these wires are wrapped in an insulating material; instead, they are typically bare and not insulated due to the high voltage and air serving as an insulator.
As for the statement regarding wood and lightning, it is true. Although wood is generally an insulator, it can conduct high voltages such as lightning because the electrical discharge is so intense that it ionizes the air and any moisture in the wood, creating a conductive path to the ground.
Regarding the use of refraction in fiber optics, it is true that refraction is useful in fiber optic cables for transmitting signals. Refraction is the bending of light as it passes from one medium to another, with different densities, and it allows light signals to travel efficiently through the fiber optic cable with minimal loss.