P1.2 Energy and Efficiency Flashcards
What are the nine types of energy?
Electrical, Light, Sound, Kinetic, Nuclear, Thermal, Gravitational Potential, Elastic Potential and Chemical
Energy can be transferred, stored or dissipated but…
It can never be created or destroyed
Energy transfer of a battery?
Chemical energy to electrical and heat energy
Energy transfer of a wind turbine?
Kinetic energy to electrical and heat energy
During energy transfers, what always happens?
Energy is wasted or lost
What happens to the wasted energy?
It is eventually transferred to cooler surroundings which become warmer. As the heat is transferred to cooler surroundings, the energy becomes less concentrated and dissipates. The amount of energy stays the same but it becomes increasingly spread out and less useful
How do you calculate efficiency?
efficiency= useful energy out divided by total energy in x 100
Is the useful energy input equal to the total energy output?
No device is 100% efficient and the wasted energy is usually lost as heat
The less energy wasted…
The more efficient the device is
What are sankey diagrams?
A way of representing energy transformations that take place in different electrical devices
What does the start of the sankey diagram show?
The total energy going into the device
What does the sankey diagram split off into?
Different sized arrows showing the other energy transfers that take place, the bigger the arrow the larger the energy
The energy entering a device must always be…
Equal to the energy leaving the device
What is useful energy?
Concentrated energy
Energy efficient light bulbs are more expensive but…
Last much longer
