A class IV laser will blind you much faster.
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∙ 2012-04-09 05:18:26Three tons is the difference between them
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differences between equator and prime meridian
give three similarities and three difference between hire purchases and deferred payment
The major difference between diploma in marine engineering and marine engineering is that in Diploma you study in a higher school or inter college also diploma is maximum of three years, on the other hand marine engineering is being studied in university and is at a higher level than diploma because it have four years and its level of study is also high.
What is the difference between the three types of ballistics
The difference between a horse is about three feet.
Three tons is the difference between them
How can you differentiate between the three types of literature?
The laser usually comes with a tripod stand. The stand has three bubble levels. You adjust the stand's three legs until the stand is level and at the height you want. Three bubbles assures it will be level in all directions. Then you turn on the laser and it will send a beam of light that is exactly level with and at the same height as the stand. You use it in all sorts of construction jobs where you need to know point A is exactly at the same height as point B. Its especiall usefull when points A & B are far apart. There are lots of different laser levels and I only described one kind. The basic idea is if the laser is level it will send out a perfectly straight light beam which you can use to make some other point the same height.
Three and Four Level Laser SchemesWe have said that the two level scheme is not generally feasible for laser action. There are two main reasons for this. The first reason is that the energy being used to pump the particles into the upper laser state has an equal probability of stimulating them back down. Thus it is not possible to get nore than half of the particles into the excited state. The three level scheme gets around this problem by first exciting the particles to an excited state higher in energy than the upper laser state.(See figure below) The particles then quickly decay down into the upper laser state. It is important for the pumped state to have a short lifetime for spontaneous emission compared to the upper laser state. The upper laser state should have as long a lifetime (for spontaneous emission) as possible, so that the particles live long enough to be stimulated and thus contribute to the gain.The four level laser scheme goes one step further and also depopulates the lower laser level by a fast decay process.(see figure below) This greatly decreases the loss of laser photons (v2) by stimulated absorption processes since the particles in the lower laser level have a short life-time for spontaneous emission.
three difference between a supercomputer and minicomputer?
Helium neon laser is better than ruby laser or most of the four level lasers are better than three level lasers due to the following reasons: The laser output is continuous in the case of helium-neon laser. But it is in the form of pulse in the ruby laser. Ruby laser requires high power pumping source, whereas Helium-neon laser requires low power pumping source like electric discharge. Efficiency of helium-neon laser is more than ruby laser. The defects due to crystalline imperfections are also present in the ruby laser. But it is not so in the helium-neon laser.
Laser therapy practitioners claim that two or three 30 minute therapy sessions of low level laser treatments will stop the urge to smoke. There is no medical or scientific evidence that this is true.
there is a three hour time difference between Kentucky and California.
The difference is 7/24 .
Currently the HP 4700DN laser printer has gotten a review of three and a half stars. The price for the HP 4700DN laser printer ranges between $300-$400.