PHYSICS · Multi-part · CBSE · Physics · Dual Nature of Radiation and Matter · Dual Nature of Radiation and Matter
Problem
A research team studies an unknown metal foil. The foil is irradiated with monochromatic ultraviolet light of wavelength 310nm, and photoelectrons are just barely emitted.
Later, the same foil is illuminated with light of wavelength 250nm. The most energetic emitted electrons are stopped by a retarding potential difference of 1.20V.
(a) Determine the work function of the metal in both joules and electron-volts.
(b) Calculate the maximum kinetic energy, in electron-volts, of the electrons emitted by the 250nm light.
(c) Using your result from part (b), predict the stopping potential required to just halt those electrons. Show how your prediction compares with the measured 1.20V value.
(d) Provide one plausible experimental reason why the measured stopping potential might differ slightly from the value you predicted.