Final answer:
The statement is true; headlight use is mandatory on U.S. installations and advised during low visibility off installations. Headlights use mirrors like lighthouses to direct beams for visibility. In the battery scenario, two 40 W headlights on a 100 Ah battery would last approximately 15 hours.
Step-by-step explanation:
The statement "However, headlight use is mandatory aboard all U.S. installations and highly encouraged during periods of reduced visibility when driving off an installation" is true. Mandatory headlight use is enforced for safety reasons to ensure visibility of vehicles during periods of limited visibility such as fog, rain, dusk, and dawn. When it comes to the operation of headlights, they utilize mirrors to form a directional beam that improves visibility. This design is similar to the reflective system in a lighthouse, which is used to warn ships away from dangerous coastlines. Regarding the calculation scenario, the driver estimates how long the headlights will last on a fully charged battery. If each headlight is 12-V and rated at 40 W, then the total power consumed by two headlights is 80 W. Given a 12-V battery rated at 100 Ah, we calculate the time for which the headlights can operate by using the formula: Ah (ampere-hour) rating divided by the current drawn by the headlights. Since power (P) is the product of voltage (V) and current (I), P = VI, the current drawn by the headlights (I) is P/V, which is 80W/12V = 6.67A. So, the headlights would last for 100Ah / 6.67A ≈ 15 hours before the battery would be drained.