• # question_answer 50) Lights of two different frequencies, whose photons have energies $1\text{ }eV$ and $2.5\text{ }eV$ respectively successively illuminate a metal whose work function is $0.5\text{ }eV$ The ratio of the maximum speeds of the emitted electrons will be A)  $1:5$              B)  $1:4$C)  $1:2$              D)  $1:1$

Einstein equation KE   = E - Work function; $\frac{1}{2}m{{v}^{2}}=E-W$ Using this concept, $\frac{\frac{1}{2}mV_{1}^{2}\max }{\frac{1}{2}V_{2}^{2}\max }=\frac{1-.5}{2.5-.5}=\frac{1}{4}$ or $\frac{{{V}_{1}}\max }{{{V}_{2}}\max }=\frac{1}{2}$