Physics - Modern Physics Question with Solution | TestHub

If photons emitted from allenalium transitions $\mathrm{n}=4\to \mathrm{n}=2$ and from $\mathrm{n}=2\to \mathrm{n}=1$ will eject photoelectron from an unknown metal but the photon emitted from the transition $\mathrm{n}=3\to \mathrm{n}=2$ will not, what are the limits (maximum and minimum possible values) of the work function of the metal ?