Question

why alkali metals show photoelectric effect with visible light? ​

Answer 1

HEYA,

Alkali metals have lower ionization energy than their counterparts and hence have higher chance of emitting electrons when a radiation falls on them. So they are used in photoelectric cells so that they easily emit electron when energy containing photons in sunlight strikes them.

Among alkali metals, cesium has lowest ionisation enthalpy and hence it can show photoelectric effect to the maximum extent and therefore preferred in photoelectric cell. The alkali metal widely used in photoelectric cells is Cs.

MARK ANSWER AS BRAINLIEST

Answer 2

Answer

The alkali metals have lowest values of  ionization energies in whole periodic table that is the reason they show photoelectric effect in visible region.

Explanation:

Photoelectric effect

• It refers to the ejection of electrons when the light of suitable frequency falls on the surface of metals .
• When light falls on the surface of metals , they eject the electrons .
• We have seen that alkali metals like Cs etc are good to make these cells as they have very low value of ionization energies due to their big size .
• Because of such low ionization energy , the ejection can be even done with visible light .
• The photoelectric effect is shown below :