swansont

you can enter 'electron volt in joules' into Google and get that, and many other, conversions. or go to onlineconversion.com 1 eV = 1.6 x 10-19J

If fusing into He-4, it would produce 23.8 MeV, but I don't think that reaction happens - too much excitation - a particle would be given off. He-3 + n gives 3.27 MeV H-3 + p gives 4.03 MeV deuterium-tritium fusion is much better, resulting in He-4 + n, and yielding 18.3 MeV

I don't think so. The pressure difference is fixed (e.g. 1 ATM inside, ~0 ATM outside). The force is proportional to the area of the hole. Smaller holes exert less force.

It should show up as an increase in temperature, and thus increased blackbody radiation (i.e. mostly IR) Whether or not you can see it easily would depend on how much energy is lost in the relaxation. From another point of view - energy is conserved. You shine a certain power of light on the fluorescent material, you get some back at the lower wavelength. The rest has to have gone somewhere - the material will heat up.

Note that that was done in a dilute vapor - hardly a physically dense material. It's optically thick because the light is on resonance.

Hence plants being green - they absorb the red and blue best.

The output power. Laser Class definitions Many laser pointers are class IIIa, so not all of that type are expensive. Also note that proper containment of a higher power laser turns it into a class I laser, so don't assume that the laser from e.g. that old CD player is safe because it's class I. Once it's out of the box or you defeat the interlock (or whatever) it's potentially dangerous.

You'd have to have two photons emitted from a single transition. (probably a necessary but not sufficient condition for entanglement) Not everything, and not always.

It depends.

As was noted, it's a problem when you let idealism drive science. Also, when you have politicians and bureaucrats run science, you can get an obscene version of Pascal's wager - fund something that, if it works, will pay tremendous dividends. But they are unable to distinguish between "difficult" and "impossible" - they just see what the payoff would be. NASA has funded a version of Podkletnov's antigravity experiment, for example.

This site gives some efficiencies. 2% for incandescents is pretty close. But LEDs aren't much more efficient, according to the list. Halogens are. Halogens run hotter, which means they give a whiter spectrum - normal incandescents look yellow - and hotter means a larger fraction of the total energy is in the visible. Which also explains why lower power incandescents are less efficient; they should be a little cooler. Another advantage of halogens is that they redeposit the tungsten on the filament, and the bulb lasts longer. Note that the link I give is the ratio of visible to total radiated power - it ignores any inefficiency in generating the EM spectrum in the first place.

Except you can't figure it that way. The potential difference is measured from ground to cloud, and won't be equal to what is measured across the cage. The current will be limited by the resistance of the atmosphere, similar to how the current through a resistor doesn't get larger when you get to the leads, which have small R. It's a series circuit. Typical discharges are of order 5,000-20,000 amps, though larger values can certainly occur.

I thought she was a riot!

It was also done in degrees C, which gives an answer of 37. Then a sloppy conversion to F was done, incorporating an extra significant digit, which gives the illusion that anything other than 98.6 F is abnormal.

<Sigh> Once again, I will point out that this is just anomalous dispersion. No violation of causality or special relativity occurred. The waves of the various frequencies that made up the wave packet were resorted, so that the peak shifted. The beam was reshaped. It's sleight-of-hand. A physics parlor trick. The peak came out earlier than it was supposed to, and the flowers are still standing. It's more bad journalism than anything else - the notion that "nothing can exceed c" is relativity oversimplified to the point that it's wrong.

No, that's not it. The superconductors aren't cooled to zero, since that's forbidden by the third law of thermodynamics. Superconductivity happens because the electrons pair up (Cooper pairs) and become Bosonic, which changes their interactions with the surrounding lattice. BCS theory is the basis of superconductivity.

They haven't cooled wires anywhere close, as compared to other things that have been cooled (BEC). R for a superconductor isn't just small, it's zero.

No, they've gotten stuff to work above liquid nitrogen temperatures - 77K - for some time now. YBa2Cu3O7-x superconducts at temperatures as high as 94K.

You aren't Emily Litella, by any chance? Never mind...

Van de Graff generators

A man was wandering around a fairground and he happened to see a fortune-teller's tent. Thinking it would be good for a laugh, he went inside and sat down. "Ah....." said the woman as she gazed into her crystal ball. "I see you are the father of two children." "That's what you think," said the man scornfully. "I'm the father of THREE children.". The woman grinned and said, "That's what YOU think.