- #1
peaches1221
- 15
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1. The amount of heat that an engine rejects to the cold reservoir is 3 times the amount of work that it does. What is the efficiency of the engine?
e = W/ Qh = 1 - Qc/Qh
For this problem, I said e= w/3w. Thus e would equal 1/3 = 0.333. This however is not correct. What did I do wrong?
2. A Carnot engine operates between the temperatures 390 K and 300 K. How much heat is discarded for the engine to produce 1900 J of work?
e = 1 - Tc/Th
e = 1 - 300K/390K = 0.2307
e = W / Qh
thus 0.2307 = 1900J/ Qh
I solved for Qh and i got the answer to be 8233.3 J
This isn't correct either, but I'm not sure what I'm doing wrong.
3. During each cycle a reversible engine absorbs 1550 J of heat from a high-temperature reservoir and performs 1200 J of work. How much heat is exhausted to the low-temperature reservoir during each cycle?
Qh = W + Qc
1550 = 1200 + Qc and then I solved for Qc. This isn't correct either.
Please Help! I am desperate and I really don't understand these problems.
e = W/ Qh = 1 - Qc/Qh
For this problem, I said e= w/3w. Thus e would equal 1/3 = 0.333. This however is not correct. What did I do wrong?
2. A Carnot engine operates between the temperatures 390 K and 300 K. How much heat is discarded for the engine to produce 1900 J of work?
e = 1 - Tc/Th
e = 1 - 300K/390K = 0.2307
e = W / Qh
thus 0.2307 = 1900J/ Qh
I solved for Qh and i got the answer to be 8233.3 J
This isn't correct either, but I'm not sure what I'm doing wrong.
3. During each cycle a reversible engine absorbs 1550 J of heat from a high-temperature reservoir and performs 1200 J of work. How much heat is exhausted to the low-temperature reservoir during each cycle?
Qh = W + Qc
1550 = 1200 + Qc and then I solved for Qc. This isn't correct either.
Please Help! I am desperate and I really don't understand these problems.