Two thin metallic coatings, Material A and Material B
PHYSICS · Multi-part · A Level · Physics · Particles and radiation · Particles and radiation
Problem
Two thin metallic coatings, Material A and Material B, are deposited side-by-side on a transparent glass slide. When illuminated with monochromatic light of frequency 7.00×1014Hz, electrons are ejected only from Material A. When the frequency is increased to 8.50×1014Hz, electrons are ejected from both coatings.
A technician measures the maximum kinetic energy of electrons from Material A at the higher frequency and finds 1.10eV.
(a) Determine the work function of Material A in electron-volts.
(b) For Material B, establish an inequality expressing the possible range of its work function based on the qualitative observations.
(c) Calculate the threshold frequency for Material B if its work function is exactly the upper bound of the range you found in part (b).
(d) If incident light of wavelength 350nm is used instead, identify which material(s) will emit electrons and justify your answer quantitatively.