Question

why are potassium and ceasium rather than litium uwed in photoelectric cells?????

Answer 1

smaller in size and therefore, requires high energy to lose an electron. Pottasium and caesiumhave much lower ionization enthalpy than that of lithium as a result, these metals exposure to light, easily emit electrons butlithium doesn`t thereforepotassium and cesium rather than lithium used in photoelectriceffect.