A student investigates the relationship between photon energy and wavelength by…
PHYSICS · Multi-part · CBSE · Physics · Dual Nature of Radiation and Matter · Dual Nature of Radiation and Matter
Problem
A student investigates the relationship between photon energy and wavelength by measuring the minimum potential difference required to stop photoelectrons emitted from a metal surface. The student records the stopping potential Vs for five different monochromatic light sources, then converts each stopping potential to photon energy E (in joules) using elementary charge information. The wavelengths λ of the light sources are provided by the manufacturer.
Trial
λ (nm)
E (×10−19 J)
1
780
2.55
2
620
3.20
3
540
3.68
4
480
4.12
5
410
4.82
(a) Convert the five given wavelengths to frequency values expressed in Hz. Show representative work for one conversion.
(b) Assuming a linear relationship between photon energy and frequency, plot E versus frequency on appropriately scaled axes (a hand-drawn plot is acceptable). Draw the best-fit straight line through the data points.
(c) Using the slope of your best-fit line, determine a value for the proportionality constant that relates photon energy to frequency. Include correct SI units.
(d) The accepted value of this proportionality constant is 6.63×10−34 J·s. Calculate the percent error of the student’s experimental value and briefly discuss one likely experimental limitation that could account for the discrepancy.