When electron beam hits phosphorus coated screen, some of the energy of these electrons in dissipated as heat and rest is transferred to electrons of phosphorus which makes them jump to higher energy levels. As we know that higher energy state is unstable and when electron comes to its original state energy is emitted in the form of light(color of light depend upon level from which electrons is returning).
In Ph, some energy levels are less stable than others so electrons in this state returns more rapidly than others.
Hence energy(in the form of light) emitted when these unstable electron return from higher state to its original state while electrons are bombarded on it is called fluorescence.
While the energy emitted when stable electrons return from higher energy levels to its original energy level once electron beam excitation is removed is called phosphorescence.
most of the light emitted in typical Ph is phosphorescence.
Persistence : It is defined as the time from removal of excitation of electron beam to the time when the phosphorescence has decayed to 10% of initial light output. Typically it is between 10-60 microsecond.
In Ph, some energy levels are less stable than others so electrons in this state returns more rapidly than others.
Hence energy(in the form of light) emitted when these unstable electron return from higher state to its original state while electrons are bombarded on it is called fluorescence.
While the energy emitted when stable electrons return from higher energy levels to its original energy level once electron beam excitation is removed is called phosphorescence.
most of the light emitted in typical Ph is phosphorescence.
Persistence : It is defined as the time from removal of excitation of electron beam to the time when the phosphorescence has decayed to 10% of initial light output. Typically it is between 10-60 microsecond.
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