North Carolina Locksmith Practice Exam 2025 - Free Locksmith Practice Questions and Study Guide

The primary function of a latch in door security is to automatically keep a door closed. Latches work by engaging with the strike plate on the door frame when the door is pushed closed, ensuring that the door remains in a secure position until it is intentionally opened. This mechanism is fundamental for providing a basic level of security, as it prevents the door from being opened without first turning the knob or using a handle, which disengages the latch.

In contrast, other functions described in the choices do not align with the core purpose of a latch. For example, unlocking a door when turned typically describes the function of a lock rather than a latch. Providing a visual indication of locking is more characteristic of specific locking mechanisms rather than a latch itself. Allowing key entry from both sides is a function associated with double-cylinder locks or specific lock sets, but not latches, which primarily serve to keep doors closed securely when not in use.