In 1905, Albert Einstein, established a relationship between mass and energy. He proposed a formula which is known as the ‘mass-energy relation’. According to this formula if mass ‘m’ is converted into energy then E=mc, where ‘c’ is the velocity of light and E is the energy released. According to this formula the energy available by the conversion of half a pound of matter will be equal to that produced by exploding 7 million tons of dynamite.
The real importance of the mass-energy relationship was realized by scientists in 1945 when the first atom bomb converting uranium into energy was exploded by USA.
On August 6, 1945, the uranium atom bomb was dropped on the Japanese city of Hiroshima. Three days later, another one, a plutonium atom bomb was dropped on Nagasaki. These bombs killed millions of people. Scientists were amazed to discover the power of nuclear energy. Later, on the basis of this formula, the more powerful hydrogen bomb was also developed.
After seeing the great destructions in Hiroshima and Nagasaki, scientists thought of making use of this energy for peaceful purposes. Nuclear power plants have been developed to generate electricity on the basis of this formula. Heat energy produced in these reactors by the fission of uranium is used for converting water into steam to run turbines, which in turn run the electric generators. These generators produce millions of megawatts of electric power. Einstein’s mass-energy relationship and its subsequent practical applications have proved to be a great boon to mankind. About 1% of energy needs of the world are now met by nuclear energy.
