About mercury

[Ignorance]

I'm sure this is a really stupid question but I have always sucked at sciences so bear with me. ^^;

 

I've been wondering if there's any chance mercury vapour could leak out of an unbroken fluorescent light bulb - or, if that were to happen, the light bulb would just never work because by then it would have nothing inside?

[YT2095]

if it`s unbroken, then no, it`ll not leak out.

as for the other, you`re Partly correct, it wouldn`t work, but not because there was "Nothing" inside, but because there would be alot More inside, these tubes are a good vacuum, so it would have to take in plenty of air 1`st, long before anything could ever leak back out

[jdurg]

The only way the mercury gets out is if the tube gets broken. You see, a fluorescent light bulb is a simple electrical gas discharge tube with a coating inside of it that emits light when excited. It operates in a similar manner to a neon sign. You have a glass tube with electrodes on each end. If you put a current through the tube, you won't see anything as air has a very high resistance to it. You need MASSIVE amounts of voltage to get electricity to travel though air (I.E. Lightning). In order to decrease this resistance, you need to lower the amount of air inside the tube. The lower the gas pressure inside the tube, the easier it is to carry a current through it. By evacuating the tube to a near vacuum, electricity flows EASILY through the tube at a relatively low voltage.

 

In a flourescent tube you have a near vacuum inside the glass tube as well as a tiny, miniscule drop of mercury. The mercury drop is placed in the tube and then the tube is sealed shut and evacuated. This causes the mercury to evaporate into a gas inside the tube due to the very low pressure. When a current is run through the tube, a blue light is given off by the excited mercury. The phosphorescent coating inside the tube absorbs these wavelengths of light and then flouresces the bright, "white" light that you see from a fluoresecent light bulb. The amount of Hg in the light bulb is almost nothing as too much Hg would require a much higher voltage in order to transmit the electricity. If a hole develops that allows the Hg to escape, then the tube would no longer work as the resistance inside the glass would be far too high.

[Ignorance]

Thank you so much for the info, guys!

 

My mind with a doubt is like a dog with a bone - it just won't let go!

I had read this explanation on how the light bulbs work

 

http://science.howstuffworks.com/fluorescent-lamp2.htm

 

but then I started wondering about the rest.

 

 

I'm feeling a lot better now, hehe!

 

 

Ps - mmmm.... yeah, the article did say low pressure in sealed tube... My attention span is pathetic...