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# Energy

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### Energy

1. 1.  Energy drives and control every apects of human life.It is crucial for continued human development and growth.Growth and develpoment are directly related to the availability of cheap and affordable energy. The standard of living can be correlated to the use of energy. Life is unthinkable without energy.
2. 2. Mechanical Energy  Chemical Energy  Electrochemical Energy  Electric Energy  Electromagnetic Energy 
3. 3. Mechanical energy constitutes of both kinetic energy and potential energy. Kinetic Energy  The energy possessed due to motion of an object is known as kinetic energy.Kinetic energy is of various forms such as vibrational . Rotational , translational and so on.  Kinetic energy of an object having mass m moving with the velocity v along the horizontal direction is given by  K.E.= 1/2mv2
4. 4.  Potential energy is the stored energy and is capable of doing work.Consider a ball of mass m held at a height h above the ground.The ball possesses potential energy due to its height given by:  P.E=mgh  Now,if the ball is allowed to fall under the field of gravity,it will start accelerating towards the ground,the ball will have both potential energy and kinetic energy and is given by E=P.E+K.E
5. 5.  The energy stored in the form of chemical bonds of a compound is known as chemical energy.  This energy is stored as electromagnetic forces of attraction between the atoms,ions or molecules takes place which results in releasing or absorbing of energy.
6. 6.  If the total energy of the reactants is more than that of the products,the additional energy is released and the reaction is known as an exothermic reaction.  If the energy of the reactants is less than that of the products,the energy is absorbed and the reaction is called an endothermic reaction  Thus ,the energy arising during a chemical reaction is known as the chemical energy
7. 7. A battery stroes electrical energy in the form of the chemical energy.  During a chemical reaction,ions are formed which accumulate at different electrodes of the battery. Once this battery is connected to an external circuit, a current is setup in the circuit. Thus,the accumulated charges are used to drive electrical circuits of various electronic devices.
8. 8.  Electricity is an integral part of modern society.  Consider any modern technology and you will see that it is directly or indirectly dependent on electricity.  Electricity is one of the main forms of the energy produced world-wide.  Since fossil fuels are steadily running out,electric power will be one of the most important energy forms in the future.  All materials are made of atoms.The atoms further consist of a nucleus(with protons and neutrons) at the centre and electrons orbiting around the nucleus.  All metal atoms contain some fixed number of loosely bound electrons. On applying a potential difference across these metals, these electrons start moving within the surface of the metal with an average velocity k/a drift velocity. This leads to electric energy.  Generally,copper and aluminum are used for making electrical wires since these metals have a lower resistance in comparison to other metals.
9. 9. EM waves are defined as packets of energy called photons.  Each photon has a specific wavelength and frequency. The energy associated with these is k/a electromagnetic energy and is given by E=(h*f) Where h is Planck’s constant and has a value 6.63x10^(-4).
10. 10.   Energy sources which can not be replenished in a short period of time. Some Non Renewable energy sources are:-  Fossil  Fuel They are formed by the decay of dead animal and plant which was buried under the earth hundreds of thousands year ago. Example- coal and natural gas. Apart from their limited stocks, the use of fossil fuel also increase the concentration of CO2 in the atmosphere which enhances the green house effect and global warming. This leads to climatic changes.
11. 11.    The strong forces b/w the nucleons holds the nucleus together. Any change occurring in the nuclear structure results in the liberation of high amounts of energy k/a nuclear energy. The process in which 2 nucei fuse together is called nuclear fusion. This process yields large amount of energy. Eg- Nuclear fusion b/w hydrogen nuclei in sun leads to formation of helium nuclei. Also vast amount of energy is released when an unstable heavy nucleus splits into smaller nuclei. This process is k/a nuclear fission. Eg – In a nuclear power plant, uranium nuclei break apart into smaller nuclei while releasing energy. The nuclear energy is not only due to potential energy during rearrangement of nuclei but also due to conversion of matter making up the nuclei. E= mc2
12. 12.  Energy liberated from nuclear fission and fusion is 107 higher compared to energy obtained from fossil fuel for the same amount of matter. Moreover energy released is cleaner compared to that of fossil fuels.  The notable problem is that it leads to radioactive spent fuel waste. Radioactive waste management is one of the intractable problem faced worldwide. This waste should not enter the biosphere as it can affect the ecosystem.
13. 13.  Energy sources which can be generated using naturally occurring sources are k/a renewable sources of energy.  Some example of Renewable Sources of Energy:-
14. 14. The energy obtained from sun is k/a solar energy. It can be used in solar water heaters, solar cookers, and solar electric generators. Solar electricity generator converts solar energy into electric energy with the help of photovoltaic cells. Its benefits are that the sunlight is widely and easily available and it can cater to the electricity needs. The problem is that it requires huge investments and bad weather conditions pose interruption to supply of sunlight.
15. 15.  The potential energy possessed by wind is converted to mechanical energy with the help of windmills which finally generate electricity.  A large area is required with no or very less population and where wind speed is high (7-9 miles).  Costly to setup.
16. 16.  The potential energy possessed by water is converted to mechanical energy by turbines which finally generate electricity.  However, the dams and other structures are required for these which are not cost effective.
17. 17.  The heat energy present within the earth helps to generate electricity using geothermal energy plants. Water is pumped into the ground where it comes into contact with hot rocks which leads to formation of steam which is further used to generate electricity. Problem- Sites available for geothermal energy is limited.
18. 18.  Tidal energy is harnessed by making structures which are capable of rotating the turbine in order to produce electricity with the help of change in water level.
19. 19.  Energy is always conserved- it can neither be created nor be destroyed…it can only be transformed from one form to another. But the problem is that during all transformatios some energy is lost into the surroundings in the form of heat, light and sound which cannot be recovered. Moreover non renewable resources are limited. Therefore the energy resources need to be conserved.
20. 20. Some ways in which energy can be conserved are-: 1) Turn off lights and fans when not in use. 2) Car pooling, using public transport will reduce fuel consumption . 3) Use more of renewable energy as they are available in plenty and do not pollute the environment. 4) Employ energy or carbon taxes to motivate energy users to reduce their consumption.The State of California employs a tiered energy tax whereby every consumer receives a baseline energy allowance that carries a low tax. As usage increases above that baseline, the tax increases dramatically. 
21. 21. 5) One of the primary ways to improve energy conservation in buildings is to use an energy audit. An energy audit is an inspection and analysis of energy use and flows for energy conservation in a building, process or system to reduce the amount of energy input into the system without negatively affecting the output(s). This is normally accomplished by trained professionals.
22. 22. 6) Replace a regular incandescent light bulb with a compact fluorescent light bulb  CFLs use 60% less energy than a regular bulb. This simple switch will save about 300 pounds of carbon dioxide a year. 7)Wrap your water heater in an insulation blanket  You’ll save 1,000 pounds of carbon dioxide a year with this simple action. You can save another 550 pounds per year by setting the thermostat no higher than 50°C.
23. 23. 8) Move your fridge and freezer  Placing them next to the cooker or boiler consumes much more energy than if they were standing on their own. For example, if you put them in a hot cellar room where the room temperature is 30-35ºC, energy use is almost double and causes an extra 160kg of CO2 emissions for fridges per year and 320kg for freezers. 9) Take a shower instead of a bath  A shower takes up to four times less energy than a bath. To maximise the energy saving, avoid power showers and use low-flow showerheads, which are cheap and provide the same comfort.
24. 24. 10) Recycle your organic waste  Around 3% of the greenhouse gas emissions through the methane is released by decomposing biodegradable waste. By recycling organic waste or composting it if you have a garden, you can help eliminate this problem! Just make sure that you compost it properly, so it decomposes with sufficient oxygen, otherwise your compost will cause methane emissions and smell foul. 11) Reuse your shopping bag  When shopping, it saves energy and waste to use a reusable bag instead of accepting a disposable one in each shop. Waste not only discharges CO2 and methane into the atmosphere, it can also pollute the air, groundwater and soil.