PHYSICS · Multi-part · A Level · Physics · Particles and radiation · Particles and radiation
Problem
For two metals X and Y, the stopping potentials measured at two different incident light frequencies are given in the table.
Frequency ν (×1014Hz) | V0X (V) | V0Y (V)
6.0 | 0.8 | 0.2
7.0 | 1.4 | 0.8
(i) Using the data for either metal, determine the numerical value of h/e (Planck’s constant per unit charge) from the slope of the V0–ν relation.
(ii) For each metal, calculate its threshold frequency ν0 by extrapolating the linear relation to V0=0.
(iii) Hence compute the work function of each metal in electron-volt and rank X and Y in ascending order of work function.
(iv) A beam of light of wavelength 550nm is incident on both metals with the same intensity. State which metal(s) will emit photo-electrons and arrange the emitting metal(s), if any, in descending order of the maximum kinetic energy of the emitted electrons.