CONCEPTUAL QUESTIONS ON 2º LAW OF THERMODYNAMICS 1. Is a temperature difference necessary to operate a heat engine? State why or why not. 2. Definitions of efficiency vary depending on how energy is being converted. Compare the definitions of efficiency for the human body and heat engines. How does the definition of efficiency in each relate to the type of energy being converted into doing work? 3. Why-other than the fact that the second law of thermodynamics says reversible engines are the most efficient-should heat engines employing reversible processes be more efficient than those employing irreversible processes? Consider that dissipative mechanisms are one cause of irreversibility. PRACTICE PROBLEMS 1. (a) What is the efficiency of a cyclical heat engine in which 75.0 kJ of heat transfer occurs to the environment for every 95.0 kJ of heat transfer into the engine? (b) How much work does it produce for 100 k) of heat transfer into the engine? 2. The engine of a large ship does 2.00x10°J of work with an efficiency of 5.00%. (a) How much heat transfer occurs to the environment? (b) How many barrels of fuel are consumed, if each barrel produces 6.00x10°) of heat transfer when burned? 3. (a) How much heat transfer occurs to the environment by an electrical power station that uses 1.25×10“) of heat transfer into the engine with an efficiency of 42.0%? (b) What is the ratio of heat transfer to the environment to work output? (c) How much work is done?
CONCEPTUAL QUESTIONS ON 2º LAW OF THERMODYNAMICS 1. Is a temperature difference necessary to operate a heat engine? State why or why not. 2. Definitions of efficiency vary depending on how energy is being converted. Compare the definitions of efficiency for the human body and heat engines. How does the definition of efficiency in each relate to the type of energy being converted into doing work? 3. Why-other than the fact that the second law of thermodynamics says reversible engines are the most efficient-should heat engines employing reversible processes be more efficient than those employing irreversible processes? Consider that dissipative mechanisms are one cause of irreversibility. PRACTICE PROBLEMS 1. (a) What is the efficiency of a cyclical heat engine in which 75.0 kJ of heat transfer occurs to the environment for every 95.0 kJ of heat transfer into the engine? (b) How much work does it produce for 100 k) of heat transfer into the engine? 2. The engine of a large ship does 2.00x10°J of work with an efficiency of 5.00%. (a) How much heat transfer occurs to the environment? (b) How many barrels of fuel are consumed, if each barrel produces 6.00x10°) of heat transfer when burned? 3. (a) How much heat transfer occurs to the environment by an electrical power station that uses 1.25×10“) of heat transfer into the engine with an efficiency of 42.0%? (b) What is the ratio of heat transfer to the environment to work output? (c) How much work is done?
Related questions
Question
Expert Solution
This question has been solved!
Explore an expertly crafted, step-by-step solution for a thorough understanding of key concepts.
This is a popular solution!
Trending now
This is a popular solution!
Step by step
Solved in 4 steps with 4 images