This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: miscellaneous, Subject name: Dental
Woods lamp has a frequency of - 
Select and explain. 
A. 250 nm, B. 300 nm, C. 320 nm, D. 360 nm
D: 360 nm
Answer: D: 360 nm 
Explanation: <p>WOOD'S LAMP Hand held device used to diagnose various dermatological conditions.It is a mercury vapour long wave,ultraviolet lamp with an inbuilt wood's filter made of barium silicate with 9% nickel oxide. Opaque to all wavelengths except those between 320 nm and 400 nm with a peak at 365 nm. Flourescence occurs when wood's light is absorbed and radiation of longer wavelengths is emitted.Examination done in dark room. Iadvl textbook of dermatology page 109