Topic 5 Energy Flashcards
What unit is energy measured in.
Joules (J)
What is the definition of energy
Energy cannot be created or destroyed. It can only be transferred from one type to another
Which energy raises the temperature of an object
Thermal or heat
Which energy does an object have when it is moving
Kinetic
Which energy is produced by vibrations
Sound
Which energy allows us to see things
Light
Which energy is found in batteries, fuel or food
Chemical
Which energy is carried in an electrical circuit
Electrical
Which energy is in an object that is high up and about to fall?
Gravitational potential
Which energy is in a stretched elastic band
Elastic potential
In an energy transfer diagram you have to state what the input energy is and the output energy is.
For a TV state the input and output energy that you would include in an energy transfer diagram
Input is ELECTRICAL ————> Output energy is LIGHT AND SOUND ENERGY
What is the energy transfer diagram for a stretched elastic band that is then released
ELASTIC POTENTIAL ——-> KINETIC ENERGY
How many Joules are there in a kilojoule
1000J
What is the energy transfer in a person eating a plate of pasta
CHEMICAL ENERGY ———->HEAT ENERGY + KINETIC ENERGY
Not all energy is useful when used and some is wasted. In a TV can you name a waste form of energy that would be produced
heat energy
Efficiency measures how much of the energy that is input into an object is used usefully in the output energy.
If an object has an input energy of 100 J and only 40J is used usefully, how much waste energy is produced
100 J input - 40J useful = 60J waste energy
In a machine if 50J is input energy and 25J is useful. What is the % efficiency?
%efficiency = useful energy/ input energy x 100
25J useful/ 50 J input = 0.5
0.5 x100% = 50%
What is meant by non renewable energy
Energy that will eventually run out and cannot be replaced
Give 3 examples of non renewable energy sources
Coal
Oil
Gas
Nuclear
What is meant by renewable energy
Energy that can be replaced and will not run out
Give 4 examples of renewable energy
Solar
Wind
Hydroelectric
Tidal
Biomass
What is a problem with renewable energy resources
It is not always windy (for windmills)
It is not always light (for solar)
Some people think it is unsightly eg wind farms
Takes up habitat spaces eg hydroelectric dams
What is a problem with non renewable resources
Cause pollution of air
Will eventually run out
How is coal formed
Dead plants and animals that died millions of years ago
Did not decay but got buried under mud and earth
Pressure and heat over time changed them to coal
