Recent content by Fe-56

:!) YES, that's it! :!) so...there must be degeneracy in all eigenvalues of A, yes? thankx a lot... ...and this was not any homework, someone replaced it from QT:))

hello...this might look very stupid but I am totally confused... Let have operators A, B, C. Let [A,B]=[A,C]=0 and [B,C] not 0... When two operators commute, they have the same base in (Hilbert) space. So base in A representation is the same as in the B representation and also the basis...

No, I really do not know to play such note :smile: :smile: :smile: :smile: :smile:

Electrons do not move around the atoms. In Bohr model, Bohr had to postulate (3rd postulate) that electrons do not radiate electromagnetic energy according to the classical electrodynamic laws because they would loose energy and fall to the core in (I don't know exactly now) about 10^-15 s...

Could be good definition that mass is that m in the equotation F=d(mv)/dt? but how can we define that F now? :-))

hm, and what is mass?:)

now there is sum of all forces affecting the body zero. So F=0=dp/dt...so...dp/dt=0...so...p=const...v=const...and that's it.

THANKS A LOT...... I think I am starting to understand at last...:!) SO, let there be an absolutely isolated body or gas...let the atoms MOVE and let ALL the atoms to be NON-excited. Now, the collisions between atoms can be INELASTIC what results such atoms are excited (like in...

yes. exactly. and the time the fridge is running depends on amount of energy for the fridge in the system at the beggining. (sealed system).

or we can believe the simplicity and beauty of our Universe :-)) (and 2 is much more "pretty" number than 1.999874564864613513243)

I think... ..while the fridge is running, the temperature in front of the door is really falling (your cooling effect) and the temperature behind the fridge is rising, but more than it is falling in front of the door... after some time the fridge will consume all the energy added...and...

I will try again :smile: OK. At first, does (black) body with temperature higher then its environment radiate if there is no radiation around it to absorb?? (now the expression black is useless) IF SO (!), I am trying to ask how is described this process...(because it has to be change...

hmmm...thanks...but I still cannot understand sth... you say, blackbody radiation is radiation of some body that is absorbing everything and continuously emiting all absorbed photons. And this is process running in electron clouds around atoms according to Bohr postulates... ok...I...

time.... :-))

please...I cannot find this anywhere....:frown: