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Unformatted text preview: Discussion Section Problems;
1) Suppose a lake has a surface area of 10000m2. water at the surface of the lake is warmed to a temperature of 298K by heat from the sun. water at the bottom of the lake is
20 degrees lower in temperature. It is proposed that a heat engine be placed in the lake
that will exploit this temperature gradient to produce work. It is claimed that this engine
can produce energy at an average rate of 1 MWatt (i.e. 106 Watts). Assuming the average
solar flux into the lake (i.e. the rate of energy transfer from the sun into the lake) is 500
Watts m-2, does this engine violate: 1) the First Law of Thermodynamics; 2) the Second
Law of Thermodynamics; 3) both the First and Second Law; 4) neither the First or the
Second Law. E...
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- Spring '09