Liquid Penetrant Testing Level 2 (PT-2) Practice Exam

The output of a mercury vapour black light depends on which factors?

1. Cleanliness of its filter

2. Age of the bulb

3. Both a and b

4. None of the above

The correct answer is: Both a and b

The output of a mercury vapor black light is influenced by several factors, primarily the cleanliness of the filter and the age of the bulb. The cleanliness of the filter is crucial because any dirt, dust, or contaminants can obstruct the passage of ultraviolet light, reducing the effectiveness of the black light. A clean filter allows more of the ultraviolet light to reach the surface being tested, thus enhancing the visibility of any penetrant indications. If the filter is dirty, it will greatly diminish the light output, which impairs the testing process. The age of the bulb also plays a significant role in the output of the black light. Over time, bulbs can lose their efficiency and the intensity of the emitted ultraviolet radiation diminishes. An older bulb may not produce sufficient light to adequately reveal the penetrant indications, leading to potentially missed defects in the material being inspected. Considering both of these factors, it is clear that both the cleanliness of the filter and the age of the bulb are essential for maintaining optimal black light performance in liquid penetrant testing.