North Carolina Locksmith Practice Exam

What characterizes a single cylinder lock?

1. Key operation from both sides

2. Key operation from only one side

3. No key required for operation

4. Multiple key options available

The correct answer is: Key operation from only one side

A single cylinder lock is characterized by its ability to be operated with a key on only one side, typically the outside. The inside of the lock is equipped with a thumb turn or a similar mechanism, allowing for convenient access without the need for a key while ensuring secure locking capabilities from the outside. This design is particularly useful for entry points such as exterior doors, where you want to maintain security without necessitating a key from the inside. The other options do not accurately describe a single cylinder lock. For example, the operation from both sides would describe a double cylinder lock, which requires a key on both the interior and exterior sides, thus providing different security features. The notion that no key is required for operation suggests a different type of lock altogether, such as a deadbolt with a thumb latch, which differs significantly from a single cylinder setup. Finally, while multiple key options might apply to many locks, it does not specifically pertain to the defining feature of a single cylinder lock, which is its unidirectional key operation.