State two points of differentiation between spontaneous emission and stimulated emission.
Spontaneous emission
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Stimulated emission
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Excited atoms comes to ground state on its own accord
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Excited atoms comes to ground state after interaction with incident photon
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Radiations are in random direction , phase and wavelength
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Radiations are coherent , monochromatic and in same direction.
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Independent of outside circumstances
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Dependent of outside circumstances
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No metastable state exist ( ordinary exited state)
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Metastable state exist
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Number of photons emitted are less
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Number of photons emitted are more
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