This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General, Subject name: Skin
What is the wavelength of UV rays used in Woods lamp? 
Select and explain. 
A. 360 nM, B. 460 nM, C. 660 nM, D. 760 nM
A: 360 nM
Answer: A: 360 nM 
Explanation: Ans. A. 360nMA Wood's lamp generates 360-nm ultraviolet (or "black") light produced by a mercury vapor source passed through a nickel oxide filter that can be used to aid the evaluation of certain skin disorders.