An open system is described as one where____________________?
Show answer Hide answer
Answer: C. both energy and mass cross the boundaries of the system
Explanation
An open system allows both mass and energy to cross its thermodynamic boundaries. Working fluids continuously enter and exit the system control volume during operation. Heat and work interactions also occur across the boundaries of open systems. Thermodynamic systems are categorized into open, closed, and isolated systems. Control volume analysis is the standard mathematical approach for studying open systems. Conservation of mass and energy equations govern all open system processes.
Turbines, compressors, and pumps operate as open systems because fluid flows through them. Power plant boilers require open system analysis to account for continuous fuel and water entry. Jet engines ingest air and expel exhaust gases, fitting the open system definition. Option A describes a closed system where mass cannot cross the system boundary. Option B defines an isolated system where neither mass nor energy crosses boundaries. Option D describes an impossible scenario where mass crosses without accompanying energy.
- Subject
- Engineering
- Category
- Mechanical Engineering
- Topic
- —
- Difficulty
- medium
Related questions
Q1. Absolute zero pressure takes place _____________________?
Show answer Hide answer
Answer: C. when molecular momentum of the system becomes zero
Pressure in a gas is caused by molecular collisions against container walls transferring momentum. When temperature drops to absolute zero, molecular thermal motion and associated momentum completely cease. Without any m...
Q2. Designing a real engine with the exact efficiency of the Carnot cycle is___________________?
Show answer Hide answer
Answer: B. impossible
Designing a real engine with the exact efficiency of the Carnot cycle is theoretically possible, but requires extreme complexities. Achieving Carnot efficiency demands infinitely slow, reversible processes without any me...
Q3. Compared to a real gas, how does an ideal gas behave at very high pressures_________________?
Show answer Hide answer
Answer: A. more volume
Intermolecular repulsive forces dominate real gases at very high pressures, expanding their volume. Real gas molecules occupy finite physical space, unlike idealized point-mass assumptions. Consequently, real gases devia...
Q4. Barometric pressure is equivalent to_____________________?
Show answer Hide answer
Answer: A. 760 mm Hg
Standard barometric pressure is defined as the pressure exerted by a mercury column measuring exactly 760 millimeters. This classic standard corresponds to one atmosphere of pressure measured at sea level under standard...
Q5. Boyle’s law, expressed as pV = constant, applies to gases under ___________________?
Show answer Hide answer
Answer: B. only small range of pressures
Boyle law, expressed as pressure multiplied by volume equals a constant, applies accurately only over small ranges of pressures. At very high pressures, real gas molecules deviate significantly from ideal behavior due to...
Q6. Calorie functions as a measurement of
Show answer Hide answer
Answer: B. quantity of heat
A calorie is historically defined as the thermal energy required to raise water temperature. It serves directly as a unit of measurement for quantifying thermal heat energy. Calorimetry experiments utilize calories or jo...