Problem 3
Light of wavelength illuminates a metal with work function , where . Given Planck's constant and light speed , find the maximum photoelectron kinetic energy, stopping potential, and threshold wavelength. Model each stage with the appropriate conservation law or equation of motion; quantities stated as constant remain fixed during that stage. (a) Establish the governing physical relation for each stage. (b) Determine the requested observables from the stated initial conditions and constraints. (c) Check signs, dimensions, and the physical limiting behavior of the results.
problems.proof.stepOf
problems.proof.analysis
Einstein's equation balances photon energy against the work function and maximum electron kinetic energy. This follows from the chosen physical model and the stated initial conditions; the sign convention must remain consistent throughout. A dimensional check catches algebraic errors before the result is interpreted.
problems.proof.pitfall. Do not mix sign conventions or omit a system constraint; check the sign and units before interpreting the result.