Which safety feature automatically stops an elevator in case of a power outage?

• A. Emergency lighting system
• B. Emergency brake system
• C. Automatic door sensors
• D. Fire alarm system

Answer: (B)

The emergency brake system is designed to ensure the safety of passengers by automatically activating if there is a power outage or other malfunction in the elevator system. When the elevator's power is lost, the emergency brake engages, preventing the elevator from free-falling and ensuring that it remains safely halted at its last position.

This safety feature is critical for minimizing the risk of accidents that could occur during a power failure, allowing the elevator to safely come to a stop rather than descend uncontrollably. Furthermore, the emergency brake system is part of a broader set of safety mechanisms that are rigorously tested and regulated to ensure they function reliably in such situations.

The other options, while important safety features in their own right, serve different purposes. For example, the emergency lighting system provides illumination during a power failure but does not stop the elevator; automatic door sensors help prevent accidents by ensuring doors do not close on passengers, but they do not address power loss directly; and the fire alarm system is crucial for alerting occupants to a fire but does not interact directly with elevator operations in response to a power outage.