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Law of Conservation of Mass and Energy

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Rural Technology

Energy can neither be created nor destroyed. Only one form of energy can be converted into another form is law of conservation of energy. Einstein showed relation between mass and energy. It is expressed by the formulae : E = m ´ c2 ( m = matter in Kg, C = speed of light 3 ´ 108 in m/s2 ).

He showed that mass and energy can be converted into each other. But it is not possible to convert matter into energy in normal conditions. It can be done in nuclear reactors.

How much energy is stored in 1 Kg of mass?

E = m ´ c2 ( m = matter in Kg, C = speed of light 3 ´ 108 in m/s2 ) E = 1 kg ´ ( 3 ´ 108 )2 = 1 ´ 9 ´ 1016 Joules This means 1 kg of mass can release 9 ´ 1016 Joules of energy. You must have confused with the above numbers. Let’s calculate, what such amount of energy means? First convert it into calories. 4.2 Joules = 1 calories Therefore, 9 ´ 1016 Joules = (9 / 4.2) ´ 1016 calories = approx. 2 ´ 1016 calories Therefore, 1 Kg of mass contains approx. 2 ´ 1016 calories

Generally, 1 gm of oil contains 10000 calories. 1 kg of oil contains = 10000 ´ 1000 = 10000000 = 107 calories Therefore, to get 2 ´ 1016 calories energy we will need 20 lacks tons of oil. In other word, 1Kg of mass contains 20 lacks tons of oil.

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