Final answer:
Locks can fail in two modes, fail-safe and fail-secure. Fail-safe mode is preferred in emergency situations where the lock defaults to an unlocked state, while fail-secure mode is chosen in high-security areas where the lock defaults to a locked state.
Step-by-step explanation:
Locks can fail in two possible modes: fail-safe and fail-secure. In fail-safe mode, the lock defaults to an unlocked state when power is lost. This mode is preferred in situations where safety is a concern, such as emergency exits.
For example, fire exit doors are often designed to open automatically in the event of a power failure to ensure swift and easy evacuation.
In fail-secure mode, the lock defaults to a locked state when power is lost. This mode is preferred in situations where security is a priority, such as high-security areas or data centers. For instance, server rooms often use fail-secure locks to prevent unauthorized access even during a power outage.