Why are potassium and cesium, rather than lithium used in photoelectric cells?

Monjur Alahi

Why are potassium and cesium, rather than lithium used in photoelectric cells? 


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Salim Ahmed Kawsar

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Smaller in size and therefore, requires high energy to lose an electron. Pottasium and caesium have much lower ionization enthalpy than that of lithium as a result, these metals exposure to light, easily emit electrons but lithium doesn`t therefore potassium and cesium rather than lithium used in photoelectric effect.

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Salim Ahmed Kawsar

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Lithium, potassium, and cesium, are all alkali metals. But still, potassium and cesium are used in photoelectric cell and not Lithium because Li is smaller in size when compared to the other two.

On the other hand, cesium and potassium have low ionization energy. Therefore, they lose electrons easily. This property is utilized in photoelectric cells.

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