Problem 3

Monochromatic light of frequency

f=8.0\times10^{14}\,\mathrm{Hz}

illuminates a metal with work function

\phi=2.0\,\mathrm{eV}

. Use

h=4.14\times10^{-15}\,\mathrm{eV\,s}

and elementary charge

e

; neglect energy losses after emission. (a) Check whether electrons are emitted. (b) Find their maximum kinetic energy. (c) Determine the stopping-voltage magnitude. (a) Find the first requested quantity. (b) Find the second quantity. (c) Determine the final result and check its units. (a) Check the emission th (a) Check the emission threshold. (b) Find the maximum electron kinetic energy. (c) Find the stopping voltage and the metal’s threshold frequency.

problems.proof.stepOf

problems.proof.prevStep problems.proof.nextStep

K_{max}=hf-\phi=1.312\,\mathrm{eV}

problems.proof.analysis

Rearranging the governing relation isolates the first requested result. Keeping the signs explicit also checks that its direction and magnitude are physically sensible.