Work functions of copper and cesium are 4.5 eV and 1.9 eV, respectively. What are the corresponding threshold frequencies for these metals ?

Explanation

If W is the work function of metal , then threshold frequency `v_0` can be written as follows :
`v_0=W//h`
Copper , `v_0=(4.5xx1.6xx10^(-19))/(6.63xx10^(-34))=1.09xx10^(15)Hz`
Caesium : `v_0=(1.9xx1.6xx10^(-19))/(6.63xx10^(-34))=4.59xx10^(14)Hz`