Physic Labs

Problem 3

Monochromatic light of frequency f=8.0×1014 Hzf=8.0\times10^{14}\,\mathrm{Hz} illuminates a metal with work function ϕ=2.0 eV\phi=2.0\,\mathrm{eV}. Use h=4.14×10−15 eV sh=4.14\times10^{-15}\,\mathrm{eV\,s} and elementary charge ee; 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.prevStepproblems.proof.nextStep
Eγ=hf=(4.14×10−15)(8.0×1014)=3.312 eVE_\gamma=hf=(4.14\times10^{-15})(8.0\times10^{14})=3.312\,\mathrm{eV}
problems.proof.analysis

First identify the physical model and convention that match the stated setup. This fixes the signs used in the equations that follow.