Ultraviolet light means the invisible part of spectrum beyond violet. This light has always been regarded as very useful because it is used to cure certain skin disease, kill bacteria, detect counterfeit money, form vitamins, etc.
Along with the increasing extensive use of computer in financial activities, ultraviolet light has been widely applied by banks to identify the signatures of their customers in passbooks. When a customer opens a new account with a bank, the bank teller always asks him to sign on a card placed in the signature column of a passbook. When the card is removed, the trace of his signature will be left; this can be used to compare with the signature on the computer’s withdrawal slip under ultraviolet light.
Ultraviolet light certainly has many practical applications, but it may also be harmful to human beings on some occasions. To everyone’s knowledge, the direct impact of the light on the eyes for an excessive length of time may blind a person.
Even though it can cure certain skin disease, it is also very harmful to the skin. A study just completed in the United States says that the light may cause skin cancer. The ultraviolet rays of the sun have been ranked as the third most dangerous cancer-causing agent after alcohol and tobacco.
It is high time to warn sun-worshippers in the quest for a bronzed look to be careful of excessive and uncontrolled exposure to the sun.
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