Question

why lithium is not used in photoelectric cells​

Answer 1

Answer:

Potassium and caesium are used in photoelectric cells rather than lithium because potassium and caesium have much lower ionisation enthalpy than that of lithium. As a result, these two metals when subjected to light, emit electrons but lithium does not.

Answer 2

Explanation:

Photoelectric cells are made up of elements which readily give out electrons when sunlight falls on them. ... But Lithium has a small size and the electrons are attracted by a great effective nuclear charge due to which, electrons cannot escape. Hence Lithium is not used in photoelectric cells.