Franck-Hertz Experiment

Electrons are accelerated by applying a known potential between two grids inside the argon tube. When an electron has sufficient kinetic energy to excite one of argon’s outer orbital electrons and has an inelastic collision with an argon atom, the electron loses a specific amount of kinetic energy. This loss of electron kinetic energy causes a decrease in the electron current in the argon tube.

Within a very short time, the excited argon electron will fall from the excited state back into the ground state level, emitting energy in the form of photons. As the accelerating voltage is increased, the electrons undergo multiple collisions and the excitation energy of the argon atom can be determined by the differences between the accelerating voltages that cause a decrease in the current. Planck’s Constant can be determined.

Grade Level: College

Subject: Physics

Student Files

	Franck-Hertz Experiment	8.65 MB
	Franck-Hertz Experiment	3.08 MB
	Franck-Hertz Experiment	635.36 KB

Teacher Files

Download All

Featured Equipment

Franck-Hertz Experiment

As early as 1914, James Franck and Gustav Hertz discovered in the course of their investigations an energy loss in distinct steps for electrons passing through mercury vapor and a corresponding emission at the ultraviolet line of mercury.

Support

Many lab activities can be conducted with our Wireless, PASPORT, or even ScienceWorkshop sensors and equipment. For assistance with substituting compatible instruments, contact PASCO Technical Support. We're here to help.
Copyright © 2023 PASCO

Copyright Disclaimer: Section 107 of the Copyright Act of 1976 makes allowance for “fair use” for purposes of teaching, scholarship, education and research. Reproduction under any other circumstances, without the written consent of PASCO, is prohibited.

Source Collection: Lab #04