Physics for Scientists and Engineers: A Strategic Approach, Vol. 1 (Chs 1-21) (4th Edition)
4th Edition
ISBN: 9780134110684
Author: Randall D. Knight (Professor Emeritus)
Publisher: PEARSON
expand_more
expand_more
format_list_bulleted
Videos
Textbook Question
Chapter 21, Problem 28EAP
A Carnot engine whose hot-reservoir temperature is 400°C
has a thermal efficiency of 40%. By how many degrees should
the temperature of the cold reservoir be decreased to raise the
engine's efficiency to 60%?
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solution
Students have asked these similar questions
A Carnot engine works at high temperature
710°F with the efficiency of 40.2%. If the
efficiency of the engine is 65.8% and the low
temperature kept constant, what is the high
temperature in °F?
A Carnot engine has an
efficiency of 30% when the
temperature of the sink is 122°
F. Then the efficiency is
increased to 70% by changing
the source temperature only.
What is the change in
temperature of the source?
A certain Carnot engine was built in a laboratory. The lab technicians found out that if the temperature of the cold reservoir is kept at 295 K, the efficiency of the engine is 26.0%. If the hot reservoir is kept at constant temperature, at what temperature must the cold reservoir be set, so that the efficiency of the engine is increased to 33.0%?
Chapter 21 Solutions
Physics for Scientists and Engineers: A Strategic Approach, Vol. 1 (Chs 1-21) (4th Edition)
Ch. 21 - Prob. 1CQCh. 21 - Rank in order, from largest to smallest, the...Ch. 21 - Prob. 3CQCh. 21 - FIGURE Q21.4 shows the pV diagram of a heat...Ch. 21 - Rank in order, from largest to smallest, the...Ch. 21 - FIGURE Q21.6 shows the thermodynamic cycles of two...Ch. 21 - A heat engine satisfies Wout= Qnet. Why is there...Ch. 21 - Prob. 8CQCh. 21 - Prob. 9CQCh. 21 - Prob. 10CQ
Ch. 21 - Prob. 11CQCh. 21 - Prob. 1EAPCh. 21 - Prob. 2EAPCh. 21 - Prob. 3EAPCh. 21 - Prob. 4EAPCh. 21 - Prob. 5EAPCh. 21 - Prob. 6EAPCh. 21 - The power output of a car engine running at 2400...Ch. 21 - Prob. 8EAPCh. 21 - Prob. 9EAPCh. 21 - Prob. 10EAPCh. 21 - Prob. 11EAPCh. 21 - Prob. 12EAPCh. 21 - Prob. 13EAPCh. 21 - Prob. 14EAPCh. 21 - Prob. 15EAPCh. 21 - Prob. 16EAPCh. 21 - A heat engine uses a diatomic gas in a Brayton...Ch. 21 - At what pressure ratio does a Brayton cycle using...Ch. 21 - Prob. 19EAPCh. 21 - Prob. 20EAPCh. 21 - Prob. 21EAPCh. 21 - Prob. 22EAPCh. 21 - Prob. 23EAPCh. 21 - Prob. 24EAPCh. 21 - Prob. 25EAPCh. 21 - Prob. 26EAPCh. 21 - Prob. 27EAPCh. 21 - A Carnot engine whose hot-reservoir temperature is...Ch. 21 - Prob. 29EAPCh. 21 - A heat engine operating between energy reservoirs...Ch. 21 - Prob. 31EAPCh. 21 - A Carnot refrigerator operating between —20°C and...Ch. 21 - The coefficient of performance of a refrigerator...Ch. 21 - A Carnot heat engine with thermal efficiency 1/3...Ch. 21 - Prob. 35EAPCh. 21 - Prob. 36EAPCh. 21 - A heat engine with 50% of the Carnot efficiency...Ch. 21 - Prove that the work done in an adiabatic process i...Ch. 21 - Prob. 39EAPCh. 21 - Prob. 40EAPCh. 21 - An ideal refrigerator utilizes a Carnot cycle...Ch. 21 - Prob. 42EAPCh. 21 - There has long been an interest in using the vast...Ch. 21 - A Carnot heat engine operates between reservoirs...Ch. 21 - A Carnot engine operates between temperatures of...Ch. 21 - Prob. 46EAPCh. 21 - A Carnot heat engine and an ordinary refrigerator...Ch. 21 - 48. A heat engine running backward is called a...Ch. 21 - 49. A car's internal combustion engine can be...Ch. 21 - Prob. 50EAPCh. 21 - Prob. 51EAPCh. 21 - Prob. 52EAPCh. 21 - Prob. 53EAPCh. 21 - Prob. 54EAPCh. 21 - Prob. 55EAPCh. 21 - Prob. 56EAPCh. 21 - Prob. 57EAPCh. 21 - A heat engine using a monatomic gas follows the...Ch. 21 - Prob. 59EAPCh. 21 - Prob. 60EAPCh. 21 - Prob. 61EAPCh. 21 - Prob. 62EAPCh. 21 - Prob. 63EAPCh. 21 - Prob. 64EAPCh. 21 - Prob. 65EAPCh. 21 - Prob. 66EAPCh. 21 - Prob. 67EAPCh. 21 - Prob. 68EAPCh. 21 - Prob. 69EAPCh. 21 - Prob. 70EAPCh. 21 - A refrigerator using helium gas operates on the...Ch. 21 - Prob. 72EAPCh. 21 - The gasoline engine in your car can be modeled as...Ch. 21 - Prob. 74EAP
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, physics and related others by exploring similar questions and additional content below.Similar questions
- A 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_forwardAn ideal gas is taken from an initial temperature Ti to a higher final temperature Tf along two different reversible paths. Path A is at constant pressure, and path B is at constant volume. What is the relation between the entropy changes of the gas for these paths? (a) SA SB (b) SA = SB (c) SA SBarrow_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_forward
- True or False: The entropy change in an adiabatic process must be zero because Q = 0.arrow_forward(a) What is the hot reservoir temperature of a Carnot engine that has an eficiency of 42.0% and a cold reservoir temperature of 210C ? (b) What must the hot reservoir temperature be for a real heat engine that achieves 0.700 of the maximum eficiency, but still has an efficiency of 42.0% (and a cold reservoir at 27.0C )? (c) Does your answer imply practical limits to the efficiency of car gasoline engines?arrow_forwardA thermal engine produces 4 MJ of electrical energy while operating between two thermal baths of different temperatures. The working substance of the engine discharges 5 MJ of heat to the cold temperature bath. What is the efficiency of the engine?arrow_forward
- How could you design a Carnot engine with 100% efficiency?arrow_forwardAt point A in a Carnot cycle, 2.34 mol of a monatomic ideal gas has a pressure of 1 4000 kPa, a volume of 10.0 L, and a temperature of 720 K. The gas expands isothermally to point B and then expands adiabatically to point C, where its volume is 24.0 L. An isothermal compression brings it to point D, where its volume is 15.0 L. An adiabatic process returns the gas to point A. (a) Determine all the unknown pressures, volumes, and temperatures as you f ill in the following table: (b) Find the energy added by heat, the work done by the engine, and the change in internal energy for each of the steps A B, B C, C D, and D A (c) Calculate the efficiency Wnet/|Qk|. (d) Show that the efficiency is equal to 1 - TC/TA, the Carnot efficiency.arrow_forwardA heat engine operates between two temperatures such that the working substance of the engine absorbs 5000 J of heat from the high-temperature bath and discharges 3000 J to the low-temperature bath. The rest of the energy is converted into mechanical energy of the turbine. Find (a) the amount of work produced by the engine and (b) the efficiency of the engine.arrow_forward
- A refrigerator has 18.0 kJ of work done on it while 115 kJ of energy is transferred from inside its interior. What is its coefficient of performance? (a) 3.40 (b) 2.80 (c) 8.90 (d) 6.40 (e) 5.20arrow_forwardOf the following, which is not a statement of the second law of thermodynamics? (a) No heat engine operating in a cycle can absorb energy from a reservoir and use it entirely to do work, (b) No real engine operating between two energy reservoirs can be more efficient than a Carnot engine operating between the same two reservoirs, (c) When a system undergoes a change in state, the change in the internal energy of the system is the sum of the energy transferred to the system by heat and the work done on the system, (d) The entropy of the Universe increases in all natural processes, (e) Energy will not spontaneously transfer by heat from a cold object to a hot object.arrow_forwardA sample of a monatomic ideal gas is contained in a cylinder with a piston. Its state is represented by the dot in the PV diagram shown in Figure OQ18.9. Arrows A through E represent isobaric, isothermal, adiabatic, and isovolumetric processes that the sample can undergo. In each process except D, the volume changes by a factor of 2. All five processes are reversible. Rank the processes according to the change in entropy of the gas from the largest positive value to the largest-magnitude negative value. In your rankings, display any cases of equality. Figure OQ18.9arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
College PhysicsPhysicsISBN:9781938168000Author:Paul Peter Urone, Roger HinrichsPublisher:OpenStax College
Physics for Scientists and Engineers: Foundations...PhysicsISBN:9781133939146Author:Katz, Debora M.Publisher:Cengage Learning
Principles of Physics: A Calculus-Based TextPhysicsISBN:9781133104261Author:Raymond A. Serway, John W. JewettPublisher:Cengage Learning
Physics for Scientists and Engineers, Technology ...PhysicsISBN:9781305116399Author:Raymond A. Serway, John W. JewettPublisher:Cengage Learning
Physics for Scientists and EngineersPhysicsISBN:9781337553278Author:Raymond A. Serway, John W. JewettPublisher:Cengage Learning
College Physics
Physics
ISBN:9781938168000
Author:Paul Peter Urone, Roger Hinrichs
Publisher:OpenStax College
Physics for Scientists and Engineers: Foundations...
Physics
ISBN:9781133939146
Author:Katz, Debora M.
Publisher:Cengage Learning
Principles of Physics: A Calculus-Based Text
Physics
ISBN:9781133104261
Author:Raymond A. Serway, John W. Jewett
Publisher:Cengage Learning
Physics for Scientists and Engineers, Technology ...
Physics
ISBN:9781305116399
Author:Raymond A. Serway, John W. Jewett
Publisher:Cengage Learning
Physics for Scientists and Engineers
Physics
ISBN:9781337553278
Author:Raymond A. Serway, John W. Jewett
Publisher:Cengage Learning
The Second Law of Thermodynamics: Heat Flow, Entropy, and Microstates; Author: Professor Dave Explains;https://www.youtube.com/watch?v=MrwW4w2nAMc;License: Standard YouTube License, CC-BY