Recent content by I<3NickTesla

So is the number given as the work provided by a Carnot engine the difference between the work done by the gas expanding and the work you have to do on the gas to compress it back to its original state?

Thanks for getting back so quickly. I thought the point of a heat engine was to convert heat into work, so it seems weird if we have to do work on the system to make it function. Is there some sort of feedback where the work done by the expansion is stored, then used to compress the gas again...

Homework Statement I think I understand the first 3 steps of the Carnot cycle but not the 4th. Homework Equations The cycle here: http://en.wikipedia.org/wiki/Carnot_cycle#Stages The Attempt at a Solution I understand that in stage 1, the gas expands by taking in heat from the hot reservoir...

The definitions of D and H are: ##D=\epsilon_0 E+P## ##H=B/\mu_0-M####P=\epsilon_0 \chi E## ##M=\chi H## I was wondering, if E and B are the fundamental field relating to all charges/currents, why is the definition of the polarisation the opposite for each of them? So why is H in the...

My question was where do periodic boundary conditions come into the problem at all? Since I've never seen that last equation before, I feel like you might be hijacking my thread. No offence, I<3NickTesla

In my particles course, it says we will use Fermi's golden rule to work out rates. FGR is: Γ=2π|Mfi|ρ For the case of non-relativistic phase space, my notes say the density of states can be found as follows (pretty much word for word): Apply boundary conditions Wave-function vanishing at box...

Realised I probably posted this in the wrong forum before, should've been here.. I often see a function's differential expressed in terms of convenient partial derivatives eg dU=(dU/dT) dT + (dU/dV) dV And I've seen it written that "any system is uniquely specified by two parameters, such...

In my diffraction notes, this integral comes up on the page about Babinet's principle: \int ^{y=\infty}_{y=-\infty} \int ^{x=\infty}_{x=-\infty} exp(-i(px+qy)) dx dy = \delta (p,q) I'm not sure how this integral is derived as carrying out the integration and putting in the limits seems to...

That helped, thanks

In the picture attached I understand everything up to 1.12. I wrote "think of it like a matrix" at the time and that made sense but now I don't really get it. There's obviously an analogy between decomposing a matrix into its eigenvector basis and a function into its eigenfunction basis but I'm...