I come from the methamphetamine capital of the world (well, not really, but it seems that way). starfish is correct on both counts; it takes very little to casue a meth lab to catch fire and/or explode. It is a menace out in riverside.
A light buld completely filled with gasoline will not explode. You would need to fill the light bulb enough so that the element was out of the gasoline. That limits to explosion to a small one, but more than enough to ignite the vapours that fill the average lab.
On an interesting side note (at least to me) it turns out that people who haven’t slept in several days really shouldn’t be working with explosive chemicals. Here is a list of the chemicals that may be used in meth labs. It comes from a public health site, so I don’t think I’m violating any policies. Note that a bunch of these are explosive.
Chloroform, Starting Fluid, Anhydrous Ammonia, “Heet”,White Gasoline,Phenyl-2-Propane,Phenylacetone, Phenylpropanolamine
Iodine Crystals, Red Phosphorous, Black Iodine,Lye (Red Devil Lye), Drano, Muriatic/Hydrochloric Acid, Battery Acid/Sulfuric Acid, Epsom Salts, Batteries/Lithium, Sodium Metal.
Also note that meth labs smell bad. Very bad. “Cat Urine” is the usual description. So they get closed up tight, in the desert. The flash point of many of the above chemicals is well below the 90-110 degrees that meth labs operate in.
Sorry, I have no way of describing how large the explosion generated by the light bulb is. Hope this helps answer your question, though.