Final answer:
The safety belt light is to remind occupants to fasten their belts and will usually turn off once belts are fastened. It may mistakenly stay on due to a surge of electrical demand when the engine starts,
Step-by-step explanation:
The safety belt light in a car serves as a reminder to fasten safety belts for the safety of the occupants. It is typically designed to be off when safety belts are not fastened and turns on when the vehicle's engine is running as a signal to the driver and passengers to buckle up.
Contrary to the statement provided that it is on when safety belts are fastened, the light should actually turn off once the safety belts are correctly engaged or fastened.
In terms of electrical behavior, when an engine starts, the car's electrical system can experience a temporary surge of high demand for power.
An analogy for this is seen with a refrigerator light: as the refrigerator's motor starts up, the light may dim momentarily due to the sudden increase in electrical usage.
A similar phenomenon may occur in a car when starting the engine, leading to dimming of internal lights such as the passenger compartment light. This effect is due to the resistance inside the battery itself.