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Franck-Hertz Apparatus, complete with DC Current Amplifier and Power Supplies I and II.

Products

2674239
SE-9639
Franck-Hertz Apparatus

Franck-Hertz Apparatus

SE-9639   - 

Stand-alone system for fundamental constants classic demonstrations, can also be used with the 850 Interface and PASCO Capstone software.

Also Available:

2633332
SE-9650
Franck-Hertz Tube Enclosure with Ar Tube

Franck-Hertz Tube Enclosure with Ar Tube

SE-9650   - 

2688561
SE-9645
Franck-Hertz Argon Tube

Franck-Hertz Argon Tube

SE-9645   - 

Replacement Argon Tube for PASCO's Franck-Hertz Apparatus.

Overview

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. The excited argon electron will within a very short time 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.

Includes

Franck-Hertz Apparatus
SE-9639
Franck-Hertz Tube Enclosure with Ar Tube
SE-9650
Franck-Hertz Argon Tube
SE-9645

How It Works

As early as 1914, James Frank 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 (λ= 254 nm) of mercury. They performed this experiment that has become one of the classic demonstrations of the quantization of atomic energy levels. They were awarded the Nobel Prize for this work in 1925.

Specifications

Filling gas
  • argon
Filament voltage
  • ≤ 6.3 VDC
Accelerating voltage
  • ≤ 100 VDC
Wave crest (or trough) number
  • 6
Argon tube lifespan
  • ≤ 3000 hrs