Problem 3
Monochromatic light of frequency illuminates a metal with work function , where > . Use Einstein's photoelectric equation, neglect all losses, and assume the emitted electrons are nonrelativistic. Let h be Planck's constant, e > 0 the magnitude of the electron charge, and m_e its mass. Find the maximum kinetic energy K_max, the stopping potential magnitude V_s, and the maximum electron speed. Assume monochromatic illumination, with each emitted electron absorbing one photon; neglect electron interactions and losses in the metal. (a) Write energy conservation for the most energetic electron. (b) Deduce the magnitude of the retarding voltage that stops it. (c) Calculate its maximum speed in the nonrelativistic approximation and state the emission threshold.
problems.proof.stepOf
problems.proof.analysis
In the photon model, each photon has energy E_gamma=h nu. The condition h nu > Phi ensures electrons are emitted.