ABO NOCE Practice Test

To test impact resistance of lenses, which object is typically used?

1. 1-inch wooden ball dropped from 60 inches

2. 5/8 inch steel ball dropped from 50 inches

3. 3/4 inch glass sphere dropped from 70 inches

4. 1-inch rubber ball dropped from 40 inches

The correct answer is: 5/8 inch steel ball dropped from 50 inches

The testing of impact resistance in lenses is a critical component of evaluating their safety and durability. The use of a 5/8-inch steel ball dropped from 50 inches is standard for this purpose because it simulates the impact forces that lenses may encounter during everyday use, especially in environments where they might be subjected to sudden shocks or hits. This specific combination of size and weight effectively provides a consistent metric for measuring how well a lens can withstand impact. Steel is stronger and denser than materials such as wood or rubber, allowing for a more rigorous assessment of a lens's capacity to resist cracking or shattering. The height of 50 inches is also significant; it is high enough to create sufficient velocity upon impact, further enhancing the realism of the test. Using a 5/8-inch steel ball also ensures that testing is uniform across different lens types. This object is specifically chosen to ensure that the results are reliable and can be correlated with real-world performance. In comparison, the other options either utilize materials that do not effectively replicate the force of common impacts or employ different sizes and weights that could compromise the consistency of test results.