Question

which metal is used to devising Photo-Chemical cell?
Li
Na
Rb
Cs​

Answer 1

Answer is Cs "Celecium"

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The ionization potentials of potassium and cesium are lower than that of lithium. On exposure to light, potassium and caesium easily emit electrons however lithium does not. Hence, potassium and caesium are used in the photoelectric cell.

Answer 2

question is -> which metal is used to devising photo - chemical cell ?

1. Li
2. Na
3. Rb
4. Cs

solution : answer is very logical.

photo chemical cell is a class of devices which converts visible light (i.e., sun light ) into electricity. means, sun light drives the chemical reaction by which electricity is generated.

it is based on the principle of photoelectric effect.

photoelectric effect says if a beam of light strikes on the metal surface, electrons ejects from the surface.

higher the tendency to remove electron from the surface of metal, higher the number of electrons will be ejected.

but tendency to eject electron increases from top to bottom in a group.

here elements Li , Na , Rb, Cs are given in which Cs is the bottom most element. so tendency to eject electrons is the highest for it.

Therefore Cs is the most preferable element among them.

Therefore correct option is option (4)