What is backlash in a gear set, and how is it measured?

What is backlash in a gear set, and how is it measured?

• A. The small gap between meshing teeth; measured with a dial indicator or by gear tooth play checks.
• B. The friction between gear teeth; measured with a dynamometer.
• C. The engagement time of gear teeth; measured with a stopwatch.
• D. The color of gear oil used; measured by pH indicator.

Answer: (A)