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
Wood&;s lamp is made up of - 
Select and explain. 
A. 9% nickel oxide with 6% BuSO4, B. 9% nickel oxide with 9% BuSO4, C. % nickel oxide with 6% BuSO4, D. 9% nickel oxide with barium silicate
D: 9% nickel oxide with barium silicate
Answer: D: 9% nickel oxide with barium silicate 
Explanation: 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. Tinea capitis-greenish fluorescence extent of pigmentation. Epidermal/dermal bacterial infection- pseudomonas infection yellowish-greeen fluorescence diagnosis of prophyria- reddish fluorescence in urine iadvl textbook of dermatology page 109