hey, i used t-5 bulbs, and yes, they have a small circumference, but when you look at bulbs, you are less interested in the "k's" and more interested in the lumens it puts out. "K's" are actually kelvins, and refer to the temperature a theoretical black substance must be heated to in order to put off that spectrum of color; ie a redish light might be rated at 2000k while a bluish-white light may be rated at 6000k (think of a piece of iron, first it glows red, then yellow, then white hot). The lumens measure the intensity of the light emitted. for example, a t5 bulb can use 24 watts to produce 1750 lumens of light with a color temp of 5000k, while a 150 watt hps (high pressure sodium) can produce 16000 lumens of a yellowish color temp around 3000k.
but back to your questions, yes they are flourescent, yes they have small circumferences, no, they probably wont work in whatever a general shop light fixture is because they are probably too short and wont fit in the end piece because of their smaller diameter than "regular" floros.
Bugus Monkey's new and improved puzzle basement and various ramblings
