A device that changes mechanical energy to electrical energy by rotatin a coil of wire through a magnetic field is called B. Generator
Disease
Lack of natural reourses
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Polution.
B explanation : they are both filled to the same pint
The basic difference is that the ordinary sources are incoherent that means that the discrete frequencies merge up to give an intermediate between the maximum and minimum frequencies. While the laser is coherent containing the single frequency with maximum amplitude. thus travelling far.