P2- Sustainable Energy

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P2- Sustainable Energy:

Energy can be stored in different forms:

Thermal

Kinetic

Gravitational potential

Elastic

Chemical

Nuclear

Electromagnetic

Electrostatic

It can be trasnferred by-

Conduction- Vibrating particles transfer energy to adjacent particles 

Convection- Energetic particles move away from hotter to cooler regions 

Radiation- Through sound waves or eleectromagnetic waves

Fossil fuels (coal, oil and gas), biofuels, wind, waves, solar radiation and nuclear fuels are all primary sources of energy.

A secondary energy source is one that is made using a primary resource. Electricity is secondary resource, and can be generated by a number of different primary sources.

Fossil fuels are formed over millions of years by the decay of dead organisms. When they are burned they produce a number of pollutants. A major pollutant formed is carbon dioxide, which contributes to global warming and climate change.

Energy is measured in joules- j

Power is measured in watts- w

The equation below shows the relationship between power (watt, W), voltage (volt, V) and current (ampere, A).

power= voltage/current

E.g. If the voltage is 12V and the current is 5A, the power is 12 x 5 = 60W

The amount of electrical energy transferred to an appliance depends on its power and the length of time it is switched on. The amount of mains electrical energy transferred is measured in kilowatt-hours, kWh. One unit is 1kWh.

The equation below shows the relationship between energy transferred, power and time:

energy transfered (kilowatt-hour, kWh) = power (kilowatt, kW) x time (hour, h)

Note that power is measured in kilowatts here, instead of the more usual watts. To convert from W to kW you must divide by 1000. For example, 2000W = 2000 ÷ 1000 = 2kW.

Also note that time is measured in hours here, instead of the more usual seconds. To convert from seconds to hours you must divide by 3600 (this is the number of seconds in 1 hour). For example,

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