Check Your Understanding What is the efficiency of a perfect
The efficiency of a perfect heat engine and the coefficient of performance of a perfect refrigerator.
Explanation of Solution
Introduction:
A device which is used to extract heat from the source and convert it into mechanical work is known as a heat engine. A perfect heat engine is the one that converts all its heat input into the work. A perfect refrigerator transports heat from a cold reservoir to a hot reservoir without work input.
The efficiency of the heat engine is the ratio of the work done and the heat input. Since a perfect heat engine converts all the input heat into mechanical work, then the efficiency of the perfect heat engine is
Conclusion:
Therefore, the efficiency of a perfect heat engine is
Want to see more full solutions like this?
Chapter 4 Solutions
University Physics Volume 2
Additional Science Textbook Solutions
Tutorials in Introductory Physics
University Physics Volume 1
The Cosmic Perspective Fundamentals (2nd Edition)
College Physics (10th Edition)
University Physics (14th Edition)
Glencoe Physical Science 2012 Student Edition (Glencoe Science) (McGraw-Hill Education)
- Suppose you want to operate an ideal refrigerator with a cold temperature of 10.0C, and you would like it to have a coefficient of performance 7.00. What is the hot reservoir temperature for such a refrigerator?arrow_forwardIs it possible for the efficiency of a reversible engine to greater than 1.0? Is it possible for the coefficient of performance of a reversible refrigerator to be less than 1.0?arrow_forwardIf a refrigerator discards 80 J of heat per cycle and its coefficient of performance is 6.0, what are (a) the quantity off heat it removes per cycle from a cold reservoir and (b) the amount of work per cycle required for its operation?arrow_forward
- Check Your Understanding A Carnot engine operates between reservoirs at 400 and 30 . (a) What is the efficiency of the engine? (b) If the engine does 5.0 J of work per cycle, how much heat per cycle does it absorb from the high-temperature reservoir? (c) How much heat per cycle does it exhaust to the cold-temperature reservoir? (d) What temperatures at the cold reservoir would give the minimum and maximum efficiency?arrow_forwardA Carnot engine has an efficiency of 0.60. When the temperature of its cold reservoir the efficiency drops to 0.55. If initially Tc=27, determine (a) the constant value of Th and (b) the final value of Tc.arrow_forwardA refrigerator has a coefficient of performance of 3.0. (a) If it requires 200 J of work per cycle, how much heat per cycle does it remove the cold reservoir? (b) How much cycle is discarded to the hot reservoir?arrow_forward
- Two hundred joules of heat are removed from a heat at a temperature of 200 K. What is the entropy change of the reservoir?arrow_forwardShow that the coefficients of performance of refrigerators and heat pumps are related by COPref=COPhp1. Start with the definitions of the COP s and the conservation of energy relationship between Qh, QC, and W.arrow_forwardTwo hundred grams of water at 0 is brought into contact into thermal equilibrium successively with reservoirs at 20 , 40 , 60 , and 80 . (a) What is the entropy change of the water? (b) Of the reservoir? (c) What is the entropy change of the universe?arrow_forward
- The Carnot cycle is represented by the temperature-entropy diagram shown below. (a) How much heat is absorbed per cycle at the high-temperature reservoir? (b) How much heat is exhausted per cycle at the low-temperature reservoir? (c) How much work is done per cycle by the engine? (d) What is the efficiency of the engine?arrow_forwardA Carnot engine operates between 550 and 20 baths and produces 300 kJ of energy in each cycle. Find the change in entropy of the (a) hot bath and (b) cold bath, in each Carnot cycle?arrow_forwardSuppose a Carnot engine can be operated between two reservoirs as either a heat engine or a refrigerator. How is the coefficient of performance of the refrigerator related to the efficiency of the heat engine?arrow_forward
- College PhysicsPhysicsISBN:9781938168000Author:Paul Peter Urone, Roger HinrichsPublisher:OpenStax CollegePrinciples of Physics: A Calculus-Based TextPhysicsISBN:9781133104261Author:Raymond A. Serway, John W. JewettPublisher:Cengage Learning