Mercury vapour black lights may be extinguished if the supply voltage drops below about:

Related MCQs

• If a mercury vapour arc black light is inadvertently turned off, how soon may it be restarted?
• What minimum warm-up time is required for acceptable performance of a mercury Vapour arc black light?
• The output of a mercury vapour black light depends on:
• When a mercury vapour black light is first turned on, what minimum warm-up time is normally required?
• When a mercury vapour black light is inadvertently cut off, approximately how long should it be allowed to cool before attempting to restart?
• The lights in a high intensity viewer are typically:
• For adequate test results, the black light used in fluorescent penetrant examination should provide what minimum black light intensity at the test surface?
• What is the likely result of looking directly into a black light?
• While performing a fluorescent water washable penetrant test, which of the following steps should be performed under black light?
• The fluorescent dyes used in the liquid penetrant testing process are most active when energised with black light of what wavelengths? (Å stands for angstrom units)