Alkali metals show photoelectric effect.Why?

Photoelectric effect: The alkali metals emit electrons when radiation strikes on their surfaces. This phenomenon of emission of electrons when electromagnetic radiation strikes against them is called photoelectric effect. Therefore, alkali metals exhibit photoelectric effect.
Explanation: Alkali metals have low ionisation enthalpies and therefore, the electrons are easily ejected when exposed to light. Among alkali metals, cesium has lowest ionisation enthalpy and hence it can show photoelectric effect to the maximum extent.