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Author Topic: It's too bright !!..Turn the dark on will you ?...A Black Light question !  (Read 3517 times)

Offline neilep

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Dear Bright Sparks ,

D'ya like my Black Light ?



It's being delivered Tuesday.

I believe it will bring instant night to the noon of my day !!

So, c'mon......why a black light ?.......is it just a regular bulb but the glass is black ?.....



Please enlighten me.....Oops..there's the door bell...I'll be right black !! *jokes are getting worse aren't they ?*










 

another_someone

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Black - as in emitting no visible light, but it does emit UV light (it may also emit significant amounts of IR light, but that is not why they are used).
 

Offline daveshorts

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There are two main ways of making the UV, you can either use a conventional bulb with a particularly hot filament and then filter out all the visible frequencies which as it sounds is horribly inefficient, or you can use a mercury based fluorescent tube (all the lighting ones are mercury based) which will glow in the UV in the same way a sodium lamp glows orange or a neon lamp red. You then just have to filter out some of the more dangerous UV frequencies. Most fluorescent lights you will find work on the second principle these days, but your picture is of the first.
 

Offline DoctorBeaver

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How fast does dark travel?  ???
 

lyner

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It follows closely on the heels of a flash of light!
 

Offline DoctorBeaver

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No matter how fast light travels, dark always gets there first.

(Terry Pratchett)
 

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