Second, I’d look at the job prospects in both areas.
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Do some emphasize hardware or software or mathematics? Which appeal to your interests and strengths? What sounds like the most fun to you? Then I’d look at the descriptions of these courses. I will just offer a couple of general guidelines.įirst, I’d look at the courses required for each concentration. I’ve done some work in control systems, but that was control of color output from printers. I was A2A but don’t have any direct experience in these EE areas. So extra heat has to leave, and for this not to violate the First Law, this has to be energy you put in as work. So if that’s all that happens, entropy will have decreased, contrary to the Second Law. And thermodynamics says this is unavoidable: to move heat from cold to hot, you must do net work.Ī slightly backwards but effective way way of seeing this is to note that according to the formula, one unit of heat entering the refrigerator from the cold side gives a larger entropy decrease to the food than the same unit of heat exiting to the hot side gives an entropy increase to the environment. But you’ll never recover all the work because you’ve cooled the gas in the radiator, so it has less pressure as it’s expanding. Now if you want to maximize efficiency, you can recover some of the work you put in to compress the gas when you let it expand.
Then you let it expand again, its temperature falls below room temperature, and the contents of the fridge can dump heat to the refrigerant. Now it can dump heat to the environment, which it does via the radiator at the back of the fridge. Its entropy doesn’t change but its temperature goes up. But if you run the compressor, you do work on the gas.
If you have refrigerant sitting in a unplugged refrigerator, no heat is going anywhere and no entropy is increasing or decreasing. Where doing work on a system can help is by giving you some control over the temperature that the heat comes and goes at. And if you do it too fast or too roughly, some of the work is effectively turned to heat and the entropy increases. infinitely slowly and gently) and the entropy doesn’t change. At best you do it “quasi-statically” (i.e. So if you want to decrease the entropy of a system, there’s absolutely no getting around exposing it to a colder temperature at some point.Ĭonversely just doing work on a system does no good at all.
By the classical definition of entropy, entropy increases or decreases only when energy flows in or out as heat.
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