Energy Transfers and Resources Flashcards
What are the different stores of energy?
Chemical, kinetic, gravitational, elastic, thermal, magnetic, electrostatic, nuclear
These stores represent the different forms energy can be found in.
How can energy be transferred mechanically?
When gravity accelerates an object, giving it kinetic energy
This illustrates the conversion of potential energy into kinetic energy.
What is an example of energy transfer by heating?
When a fire is used to heat up an object
Heating is a common method of energy transfer in everyday life.
What is energy transfer by radiation?
When vibrations cause waves to travel through the air as sound or an object emits electromagnetic radiation
This includes examples like sound waves and light.
What is the principle of energy conservation?
The total energy before is equal to the total energy after
This principle is fundamental in physics and indicates energy cannot be created or destroyed.
How is efficiency calculated?
efficiency = useful energy output / total energy input × 100%
Efficiency measures how well energy is converted into useful work.
What do Sankey diagrams represent?
The transfer of input energy into useful energy and wasted energy
Sankey diagrams visually depict energy flows and efficiencies.
What is conduction?
Thermal energy in solids and liquids can be transferred by the vibration of particles
Conduction occurs primarily in solids where particles are closely packed.
What are thermal insulators?
Non-metals that are usually poor conductors
Insulators are used to reduce unwanted energy transfer.
How do metals conduct heat?
Electrons can leave the atoms and move freely among positively charged ions
This free movement of electrons allows metals to efficiently transfer heat.
What is convection?
Thermal energy in fluids can be transferred by the movement of molecules from high to low thermal energy
Convection is essential in processes like heating water and air.
What happens when a fluid is heated?
It expands, becomes less dense, and rises
This process drives the convection currents in fluids.
Fill in the blank: Thermal energy in fluids can be transferred by _______.
convection
Convection is distinct from conduction, which occurs in solids.
True or False: All materials are good conductors of heat.
False
Non-metals are typically poor conductors and serve as insulators.
What is an example of convection in everyday life?
Water boilers and hot air balloons
These examples illustrate how convection currents operate in liquids and gases.
What is thermal energy transferred by that does not require a medium?
Infrared radiation
Infrared radiation is part of the electromagnetic spectrum.
What type of bodies are the best absorbers and emitters of radiation?
Black bodies with a dull texture
These bodies are effective due to their surface properties.
What type of bodies are the best reflectors of radiation?
White bodies with a shiny texture
Shiny surfaces can reduce unwanted energy transfer.
How does temperature and surface area affect infrared radiation emission?
Higher temperature and greater surface area increase infrared radiation emitted
This relationship is crucial for understanding thermal dynamics.
What is work done defined as?
Work done = force × distance
This equation represents the relationship between force and movement.
What does the conservation of energy link together?
Gravitational potential energy, kinetic energy, and work
This concept is fundamental in physics.
What happens to a ball’s gravitational potential energy when it is dropped?
It becomes kinetic energy as it accelerates downwards
Gravity does work on the ball during this process.
What is the formula for kinetic energy?
Kinetic energy = 1/2 mass × speed²
This reflects how speed affects kinetic energy.
What is the formula for gravitational potential energy?
Gravitational potential energy = mass × gravitational field strength × height
This formula shows how potential energy is influenced by height.
What is power a measure of?
The rate at which energy is transferred or work is done
Understanding power is essential for evaluating energy systems.
What does a lamp with greater power do compared to one with lesser power?
It transfers more energy from electrical energy to light and heat in a given time
This explains why higher wattage lamps are brighter.
Fill in the blank: Power = _______.
Work done / time
This formula provides a clear definition of power.
