Visible region of electromagnetic spectrum is not suitable for photoemission from

$$\begin{gathered} \mathrm{The} \mathrm{threshold} \mathrm{frequency} \mathrm{of} \mathrm{radiation} \mathrm{for} \mathrm{zinc} \mathrm{is} 6.5\times {10}^{14} \mathrm{Hz}. \\ \mathrm{Which} \mathrm{lies} \mathrm{in} \mathrm{ultraviolet} \mathrm{region}. \\ \mathrm{For} \mathrm{zinc} \mathrm{to} \mathrm{emit} \mathrm{electrons} \mathrm{it} \mathrm{needs} \mathrm{light} \mathrm{having} \mathrm{at} \mathrm{least} \mathrm{the} \mathrm{frequency} \mathrm{of} \mathrm{UV}. \end{gathered}$$