16 Questions
What does the efficiency of a water heater measure?
The energy delivered to the house by hot water
What is the heating value of a fuel?
The amount of heat released when burning the fuel
How is the lower heating value (LHV) different from the higher heating value (HHV)?
LHV includes the heat of vaporization, HHV does not
What does a generator do?
Converts mechanical energy to electrical energy
How is generator efficiency defined?
Ratio of electrical power output to mechanical power input
What does the thermal efficiency of a power plant measure?
Ratio of net electrical power output to fuel energy input
What is the relationship between the power of a compact fluorescent lamp and an incandescent lamp of the same light output?
The compact fluorescent lamp has 1/4 the power of the incandescent lamp
Which of the following is the best definition of mechanical efficiency?
The effectiveness of the conversion process between the mechanical work supplied or extracted and the mechanical energy of the fluid
What is the overall efficiency of a turbine-generator system?
The product of the efficiency of the turbine and the efficiency of the generator
If a fan has a mechanical efficiency of 0.80, what is the ratio of the kinetic energy of the air at the fan exit to the mechanical power input?
0.80
What is the unit of mechanical power input to a fan?
Watts
Which of the following is the correct unit for mechanical energy per unit mass?
Joules per kilogram
The rate of mechanical energy of a flowing fluid per unit mass is equal to:
The sum of the kinetic and potential energy per unit mass
The change in mechanical energy of a fluid during incompressible flow per unit mass is given by the expression:
$\frac{1}{2}v^2 + gz$
The rate of mechanical energy change of a fluid during incompressible flow is proportional to:
The mass flow rate
According to the kinetic theory, heat is the energy associated with the:
Random motion of atoms and molecules
Explore the concept of energy conversion efficiencies in thermodynamics and how they relate to processes like mass flow, heat, and work interactions. Learn about calculating the efficiency of systems such as water heaters based on energy delivered versus energy supplied.
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