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Thermal Energy and Energy Resources flashcards

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What is temperature?Temperature and Particle Motion
A property related to average particle kinetic energy in a simple model.
What is the SI temperature unit?Temperature and Particle Motion
Kelvin (K).
How do you convert Celsius to kelvin?Temperature and Particle Motion
T(K) = T(°C) + 273.15.
Does equal temperature imply equal total internal energy?Temperature and Particle Motion
No; size, composition, and state also matter.
What is internal energy?Temperature and Particle Motion
Microscopic kinetic and potential energy within a system.
What is heating?Temperature and Particle Motion
Energy transfer because of a temperature difference.
What is thermal equilibrium?Temperature and Particle Motion
No net heat transfer between contacting systems at the same temperature.
Does equal temperature mean particles stop moving?Temperature and Particle Motion
No.
What is thermal expansion?Temperature and Particle Motion
A size change associated with temperature change.
What is α in a linear expansion model?Temperature and Particle Motion
Material-specific expansion coefficient.
Why use expansion joints?Temperature and Particle Motion
To allow size changes with temperature.
Does expansion create new material?Temperature and Particle Motion
No; particle spacing can change.
What is conduction?Heat Transfer
Energy transfer through interactions among neighboring particles.
What is a thermal conductor?Heat Transfer
A material that transfers thermal energy relatively readily.
What is an insulator?Heat Transfer
A material or structure that reduces thermal transfer rate.
Can radiation cross a vacuum?Heat Transfer
Yes.
What is convection?Heat Transfer
Energy transfer involving bulk movement of fluid.
What is natural convection?Heat Transfer
Fluid movement driven by buoyancy under suitable conditions.
What is forced convection?Heat Transfer
Fluid movement driven by a fan, pump, or similar device.
Can convection occur in a vacuum?Heat Transfer
No; it requires a fluid.
What is thermal radiation?Heat Transfer
Electromagnetic energy emitted by matter due to its temperature.
Can thermal radiation travel through vacuum?Heat Transfer
Yes.
What determines net radiative gain?Heat Transfer
Incoming absorption compared with outgoing emission.
Is thermal radiation nuclear radioactivity?Heat Transfer
No.
What is specific heat capacity?Specific Heat and Phase Change
Energy transfer per mass per temperature change.
What is the heating equation?Specific Heat and Phase Change
Q = mcΔT when c is approximately constant and phase is unchanged.
What is c in SI units?Specific Heat and Phase Change
J/(kg·K).
When can Q = mcΔT fail as a simple account?Specific Heat and Phase Change
Across a phase change or varying c without added modeling.
What is latent energy L?Specific Heat and Phase Change
Energy per mass for a specified phase change.
What is the phase-change equation?Specific Heat and Phase Change
Q = mL under stated conditions.
What is evaporation?Specific Heat and Phase Change
Escape of molecules from a liquid surface.
What is boiling?Specific Heat and Phase Change
Vapor formation throughout a liquid at a pressure-dependent boiling point.
What does a sloped heating segment suggest?Specific Heat and Phase Change
Temperature change within a phase.
What does an ideal plateau suggest?Specific Heat and Phase Change
A phase transition with transfer at nearly constant temperature.
What extra information links time to energy?Specific Heat and Phase Change
Heating power and losses.
Can mixtures have non-flat phase transitions?Specific Heat and Phase Change
Yes.
What is a renewable resource?Energy Sources and Electricity Generation
One replenished on a relevant human-use timescale under stated conditions.
What is a fossil fuel?Energy Sources and Electricity Generation
Ancient carbon-rich material used as a nonrenewable energy resource.
Is nuclear fuel usually renewable?Energy Sources and Electricity Generation
No, commonly used fissile fuel is finite.
Does renewable mean impact-free?Energy Sources and Electricity Generation
No.
What is a turbine?Energy Sources and Electricity Generation
A device converting fluid-flow energy into rotation.
What is a generator?Energy Sources and Electricity Generation
A device converting mechanical energy into electrical energy by induction.
What is a photovoltaic cell?Energy Sources and Electricity Generation
A device converting some light energy directly into electrical energy.
What is an electrical grid?Energy Sources and Electricity Generation
A network transferring electric energy from sources to users.
What is electrical power?Energy Sources and Electricity Generation
Rate of electrical energy transfer.
What is a kilowatt-hour?Energy Sources and Electricity Generation
Energy used by 1 kW over 1 hour.
What is round-trip efficiency?Energy Sources and Electricity Generation
Energy recovered from storage divided by energy used to charge it.
Is rated capacity actual energy output?Energy Sources and Electricity Generation
No; duration and operating conditions matter.
What is life-cycle assessment?Environmental Tradeoffs and Energy Accounting
Evaluation of impacts across stated stages of a product or system.
What is a functional unit?Environmental Tradeoffs and Energy Accounting
A common output basis for comparison.
Why set a boundary?Environmental Tradeoffs and Energy Accounting
Included stages determine the calculated impacts.
Does low operating emissions mean zero life-cycle impacts?Environmental Tradeoffs and Energy Accounting
No.
What is an environmental tradeoff?Environmental Tradeoffs and Energy Accounting
A gain on one goal paired with a cost on another.
What is reliability in a power system?Environmental Tradeoffs and Energy Accounting
Ability to meet demand under specified conditions.
Can storage help variable generation?Environmental Tradeoffs and Energy Accounting
Yes, within capacity and efficiency limits.
Does one impact metric settle all choices?Environmental Tradeoffs and Energy Accounting
No.
What is a baseline?Environmental Tradeoffs and Energy Accounting
The starting quantity used for comparison.
What is a denominator?Environmental Tradeoffs and Energy Accounting
The reference amount in a ratio or percentage.
Why distinguish power from energy?Environmental Tradeoffs and Energy Accounting
Power is a rate; energy accumulates over time.
Does sequence alone prove causation?Environmental Tradeoffs and Energy Accounting
No.