Describe the Carnot cycle with the roles of all four processes involved
Outline the Carnot principle and its implications
Demonstrate the equivalence of the Carnot principle and the second law of thermodynamics
In the early 1820s, Sadi
Carnot (1786−1832), a French engineer, became interested in improving the efficiencies of practical heat engines. In 1824, his studies led him to propose a hypothetical working cycle with the highest possible efficiency between the same two reservoirs, known now as the
Carnot cycle . An engine operating in this cycle is called a
Carnot engine . The Carnot cycle is of special importance for a variety of reasons. At a practical level, this cycle represents a reversible model for the steam power plant and the refrigerator or heat pump. Yet, it is also very important theoretically, for it plays a major role in the development of another important statement of the second law of thermodynamics. Finally, because only two reservoirs are involved in its operation, it can be used along with the second law of thermodynamics to define an absolute temperature scale that is truly independent of any substance used for temperature measurement.
With an ideal gas as the working substance, the steps of the Carnot cycle, as represented by
[link] , are as follows.
Isothermal expansion. The gas is placed in thermal contact with a heat reservoir at a temperature
The gas absorbs heat
from the heat reservoir and is allowed to expand isothermally, doing work
Because the internal energy
of an ideal gas is a function of the temperature only, the change of the internal energy is zero, that is,
during this isothermal expansion. With the first law of thermodynamics,
we find that the heat absorbed by the gas is
Adiabatic expansion . The gas is thermally isolated and allowed to expand further, doing work
Because this expansion is adiabatic, the temperature of the gas falls—in this case, from
From
and the equation of state for an ideal gas,
, we have
so that
Isothermal compression . The gas is placed in thermal contact with a cold reservoir at temperature
and compressed isothermally. During this process, work
is done on the gas and it gives up heat
to the cold reservoir. The reasoning used in step 1 now yields
where
is the heat dumped to the cold reservoir by the gas.
Adiabatic compression . The gas is thermally isolated and returned to its initial state by compression. In this process, work
is done on the gas. Because the compression is adiabatic, the temperature of the gas rises—from
in this particular case. The reasoning of step 2 now gives
The total work done by the gas in the Carnot cycle is given by
is it possible to leave every good at the same level
Joseph
I don't think so. because check it, if the demand for chicken increases, people will no longer consume fish like they used to causing a fall in the demand for fish
Anuolu
is not really possible to let the value of a goods to be same at the same time.....
Salome
Suppose the inflation rate is 6%, does it mean that all the goods you purchase will cost
6% more than previous year? Provide with reasoning.
Not necessarily. To measure the inflation rate economists normally use an averaged price index of a basket of certain goods. So if you purchase goods included in the basket, you will notice that you pay 6% more, otherwise not necessarily.
Good day
How do I calculate this question: C= 100+5yd G= 2000 T= 2000 I(planned)=200.
Suppose the actual output is 3000. What is the level of planned expenditures at this level of output?
I am Camara from Guinea west Africa... happy to meet you guys here
Sekou
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Amisha
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Amisha
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Amisha
belatari
Amisha
1st year ho
Amisha
nd u
Amisha
ahh
Amisha
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Amisha
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Amisha
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Amisha
money as unit of account means what?
Kalombe
A unit of account is something that can be used to value goods and services and make calculations
Jim
all of you please speak in English I can't understand you're language
Muhammad
I want to know how can we define macroeconomics in one line
Muhammad
it must be .9 or 0.9
no Mpc is greater than 1
Y=100+.9Y+50
Y-.9Y=150
0.1Y/0.1=150/0.1
Y=1500
Kalombe
Mercy is it clear?😋
Kalombe
hi can someone help me on this question
If a negative shocks shifts the IS curve to the left, what type of policy do you suggest so as to stabilize the level of output?
discuss your answer using appropriate graph.