Photoelectric Effect Using a Monochromator to Determine Planck s Constant
Peer-review ID: B503
Reviewer’s name: _________________ umn ID number: _________________
Photoelectric effect: using a monochromator to measure electron energy as a function of incident photon frequency to determine Planck’s constant
John Greavu
Partners: Daniel Erickson and Kevin Haar
School of Physics and Astronomy,
University of Minnesota, Minneapolis, Minnesota 55455
24 March 2014
The energy of ejected electrons from the cathode end of an electrode due to the photoelectric effect as a function of the incident light’s frequency was measured. Using the PASCO AP-8209 Photoelectric Effect Apparatus, an experimental value for Planck’s constant h was determined: (4.27 0.0576) x 10-15 eV-s, 2.26σ from the theoretical value. This discrepancy is within the expected accuracy of the apparatus and several possible errors have been taken into account. The hypothesis that ejected electron energy is independent of the intensity of the incident light was confirmed. Also provided is a brief history and introduction to the photoelectric effect, as well as a hypothesis as to the material of the cathode. Work functions given from the intercepts of produced figures show that this is 1.72 0.0317 eV, approximately that of a typical well-activated barium oxide coating.
I. HISTORY AND INTRODUCTION
Up through the eighteenth century, particle theories of the nature of radiation—or light—held strong largely due to the work of Isaac Newton. In 1805, however, experiments such as Thomas Young’s famous double-slit experiment, objected to the consensus by demonstrating light’s wave-like properties.
In 1839, the French physicist Alexandre Edmond Becquerel became the first person to document the interaction of light with matter1. He noticed in his experiments with electrolytic cells that there was a strong relationship between light and the electronic properties of materials. Light striking a surface was found to induce a current or voltage. This
Reviewer’s name: _________________ umn ID number: _________________
Photoelectric effect: using a monochromator to measure electron energy as a function of incident photon frequency to determine Planck’s constant
John Greavu
Partners: Daniel Erickson and Kevin Haar
School of Physics and Astronomy,
University of Minnesota, Minneapolis, Minnesota 55455
24 March 2014
The energy of ejected electrons from the cathode end of an electrode due to the photoelectric effect as a function of the incident light’s frequency was measured. Using the PASCO AP-8209 Photoelectric Effect Apparatus, an experimental value for Planck’s constant h was determined: (4.27 0.0576) x 10-15 eV-s, 2.26σ from the theoretical value. This discrepancy is within the expected accuracy of the apparatus and several possible errors have been taken into account. The hypothesis that ejected electron energy is independent of the intensity of the incident light was confirmed. Also provided is a brief history and introduction to the photoelectric effect, as well as a hypothesis as to the material of the cathode. Work functions given from the intercepts of produced figures show that this is 1.72 0.0317 eV, approximately that of a typical well-activated barium oxide coating.
I. HISTORY AND INTRODUCTION
Up through the eighteenth century, particle theories of the nature of radiation—or light—held strong largely due to the work of Isaac Newton. In 1805, however, experiments such as Thomas Young’s famous double-slit experiment, objected to the consensus by demonstrating light’s wave-like properties.
In 1839, the French physicist Alexandre Edmond Becquerel became the first person to document the interaction of light with matter1. He noticed in his experiments with electrolytic cells that there was a strong relationship between light and the electronic properties of materials. Light striking a surface was found to induce a current or voltage. This