The following observations were recorded for a clean sodium surface irradiated with…
PHYSICS · Multi-part · AP · Physics 2: Algebra-based · Modern Physics · Modern Physics
Problem
The following observations were recorded for a clean sodium surface irradiated with monochromatic light of different frequencies. Each reading of stopping potential has an instrumental uncertainty of ±0.05V and each frequency has an uncertainty of ±0.05×1014Hz.
ν(1014Hz): 5.20, 5.60, 6.00, 6.40, 6.80, 7.20
V0(V): 0.30, 0.57, 0.86, 1.14, 1.44, 1.72
(i) Plot a graph of stopping potential V0 (y-axis) against frequency ν (x-axis) on a suitable scale and draw the best-fit straight line through the points.
(ii) From the slope of your graph, calculate an experimental value of Planck’s constant h (express the answer in J s).
(iii) Using the intercept, determine the work function of sodium in eV.
(iv) Propagate the given measurement uncertainties to estimate the percentage uncertainty in your value of h.