Device Definition and 509 Threads

Hello, I am stumped on this question from my textbook: I tried by using this equation which I felt should work: But it doesn't seem to get me the correct answer (which is 22 ohms). Any ideas? Thanks!

I've heard about some small chip of some kind that has termendous cooling power when a current is run through it. Apparently it is a high efficiency alternative to a large refrigerator when it is kept in a small, enclosed area. It's equivalent to something like 10 bags of ice or something, I...

Hi all, I'm looking for general information on an inductor type device which transfers AC power to a seperate, unconnected (but nearby) inductor. If I were to try googling it, what should my searchword be?

Does anyone know how to build a device to detect subatomic particles (electrons, muons, neutrinos,, and the like...?) Please, if you do, send me some instructions. Thanks.

http://www.tdimension.com/news.html I believe TEN had mentioned that these things wouldn't work in a vacuum due to ionized air flow. Well here's a lab who did sucessful testing in a vacuum. I'm sure there's a reason this cannot be harnessed, but maybe someone would fill in the blanks for me...

first thing, do you think such a device can be technologically feasible? do you think we need it? i think if we can build such a device why not?! i think the advantages of it are more than the disadvantages.

Yeah I know thermodynamics says it's a scientific impossibility, but what is the closes inventors have come to a free energy device? Or what is the best energy producing system out there for its size[?]

A laser is a device that uses light flashes to excite the atoms so you get electrons with energy levels about 2 or 3 levels above the ground state. They emit photons, which vibrate at a particular frequency, they get reflected off the half silvered mirror, to excite electrons and make them emit...

My CD_RW drive died last week and I just bought a new one. I made it the master, and the CD rom the slave. Since doing this the drive names have changed letters. I assume that is a normal thing. But also now my computer no longer recognises any imaging devices connected to my USB ports...