Connect with us

Franck-Hertz experiment is not quantized

Discussion in 'Electronic Basics' started by [email protected], Oct 12, 2005.

Scroll to continue with content
  1. Guest

    16 Franck-Hertz experiment is not quantized
    Ed 01.12.31 ----------------------------------------
    By increasing the voltage in the Franck-Hertz experiment we reach a
    breakdown voltage in which the current existent between the grid and
    anode is canceled. This breakdown voltage will be repeated at equal
    intervals by increasing the voltage.

    I. Introduction
    As an evidence that even absorption of kinetic energy by an atom is
    quantized the Franck-Hertz experiment is cited. It is said that this
    experiment shows clearly that the kinetic energy of an electron
    with an atom will be absorbed by the atom only when it is exactly equal
    to the distance between the energy levels of the electron in the atom.
    In other words, only when it has some definite amounts it'll be
    by the atom. What this article is going to show is that what occurs in
    this experiment is not really a quantum process but a simple mechanical
    and electric one rather similar to when you are trying to separate the
    apples of an apple tree by shaking its trunk. When your energy exerted
    on the trunk is not sufficient (equal to a definite amount) no apple
    will fall, but when it is the case, suddenly many apples will fall.

    II. Analysis of the Franck-Hertz experiment
    In the Franck-Hertz experiment, as shown in Fig. 1, the grid G is
    near the Anode A while the high potential difference V between G and
    cathode C is variable but the low potential difference between A and G

    | C G |
    ^^^^^^^^\ | : A |
    | | | : | |
    | | | : |-------|
    | | | : | | |
    _______/ | : | / \
    |-----|------------------------------|----| ( I )
    | /^\ | \ /
    |---------( V )----------------| V' |
    | \_/ | | | |
    |---------------| ... |--------|--||-----|
    | a |
    - + +-
    Fig. 1.

    The gas under experiment is in the lamp containing C, G and A. When C
    warmed up (electrically), the experiment starts. Variation of I, the
    current of A, with V is something like what is shown in Fig. 2 in which
    the horizontal distance between each two adjacent tops is the same.

    I | .'` .'` .'` .'`
    | . | . | . | . |
    | _-` ' _-` ' _-` ' _-` '
    | .- ` .- ` .- ` .- `
    |/` ,/` ,/` ,/`
    | V

    Fig. 2.

    The curve falls abruptly after each top (not quite normally but with a
    steep gradient).

    As I have explained in Articles 9 and 12 and 1st appendix of the book,
    electric current is a continuous process, in which an electron train is
    moving (ie as if the electrons, taking part in the current, are in
    with each other in a train of themselves each exerting force on the
    not a colliding one. Let's remove the grid G temporarily. In this
    when the cathode C has not yet been warmed no current flows in the
    But when as a stimulation C is warmed, a current of electrons will flow
    in the circuit in the direction from C to A. Why? Because, the constant
    voltage V' is smaller than V and then the situation is as if the source
    of potential in the circuit is a single battery which its negative pole
    is connected to C and its positive pole is connected to A. Thus,
    we shall have an electron current from C to A when the cathode is
    In this state let's restore G. Certainly, now, only a part of the
    will flow via the grid toward the point a, and the rest of it still
    toward A (through the holes in the grid).

    Now let's consider the right circuit consisting of G, A and V' before
    warming the cathode up, ie before causing any current to flow in the
    circuit. In this state, what can cause an electron current to flow in
    this (sub)circuit from A to G? Just the same factor that causes an
    electron current in the main circuit from C to A, ie (the stimulation
    caused by) heat. But we have not given any external (electric) heat to
    space between A and G as done in the main circuit when warming C up.
    That's right, but such a heat can be provided by the electric current
    flowed in the space between G and A. Such a heat should be sufficient
    if it is to cause freedom of the electrons of the atoms of the gas from
    these atoms and an electron current in the right (sub)circuit from A to
    G, otherwise there won't be such a current even though the space
    between G and A is warmed (insufficiently).

    Thus, if the total current in the circuit, from C to G, is sufficiently
    intense (which this occurs when V is sufficiently high), sufficient
    due to passing of the electron current from G to A, will be produced to
    cause freedom of the electrons of the atoms ie stimulation of the right
    circuit to cause an electron current to flow from A to G. But this
    electron current from A to G will cancel the main electron current in
    main circuit from G to A, and the result is that there will be no
    practically. When there is no current in the space between G and A,
    there won't be any heat produced due to it, and then there
    won't be any stimulation to cause any electron current (in the right
    circuit) to flow from A to G, and then the story can be repeated, ie by
    increasing the voltage V, the electron current is again increased until
    when the heat produced due to it stimulates the voltage V' to cause an
    equal but opositely directed electron current to flow causing a renewed
    fall in the curve of I against V just at a point as far from the
    point of fall as the next point of fall.

    Of course, in the real curves, each (new) peak is (a little)
    higher than the previous one. What presented above excluded
    this aspect of the experiment as an unimportant thing for the general
    justification of the main result of the experiment (ie existence of
    repeated falls in the curve at equal distances).
    What can be said at present for the probable cause of this effect is
    that by increasing the voltage there may be some electrons flowing from
    Cathode to Anode due to field emission. These electrons themselves make
    a ground current having no relation to the current produced by
    of the valence electrons of the atoms of the gas in the tube. Only this
    recent current (ie one due to displacing of the valence electrons of
    gas atoms) can give heat to the atoms (causing separation of their
    electrons if this heat is sufficiently big), because the electrons of
    only this current are in direct contact with the atoms. This suggestion
    can probably be tested by study on any alteration in the results of the
    experiment when we try to eliminate as many causes for the field
    emission as possible.

    Hamid V. Ansari

    My email address: ansari18109<at>yahoo<dot>com

    The contents of the book "Great mistakes of the physicists":

    0 Physics without Modern Physics
    1 Geomagnetic field reason
    2 Compton effect is a Doppler effect
    3 Deviation of light by Sun is optical
    4 Stellar aberration with ether drag
    5 Stern-Gerlach experiment is not quantized
    6 Electrostatics mistakes; Capacitance independence from dielectric
    7 Surface tension theory; Glaring mistakes
    8 Logical justification of the Hall effect
    9 Actuality of the electric current
    10 Photoelectric effect is not quantized
    11 Wrong construing of the Boltzmann factor; E=h<nu> is wrong
    12 Wavy behavior of electron beams is classical
    13 Electromagnetic theory without relativity
    14 Cylindrical wave, wave equation, and mistakes
    15 Definitions of mass and force; A critique
    16 Franck-Hertz experiment is not quantized
    17 A wave-based polishing theory
    18 What the electric conductor is
    19 Why torque on stationary bodies is zero
    A1 Solution to four-color problem
    A2 A proof for Goldbach's conjecture
  2. --

    Michael A. Terrell
    Central Florida
  3. In sci.physics, Michael A. Terrell

    "The"? ;-) We've a few here in sci.physics; I can't say regarding
    sci.electronics.basics, admittedly.

    You're welcome to borrow one or two of 'em, of course...just make
    sure to return them in good condition.
  4. Uncle Al

    Uncle Al Guest

    [snip crap]

    Never trust an idiot who cannot count beyond fingers and toes.

  5. If I can't use them for target practice, I don't want them.

    I found an old set of lawn darts the other day, I wonder which is
    harder, their skulls, ot the steel tips? ;-)

    BTW, there is a real one on . If you
    ignore him, he will call you and make threats.
  6. Harry

    Harry Guest

    At first sight that look like Trichel pulses. Who claims that this is a
    quantum effect, and where?

  7. Kitchen Man

    Kitchen Man Guest

    Or starts a numbered list with zero.
  8. I do, as does anyone that knows 101 physics.

    Kevin Aylward
    SuperSpice, a very affordable Mixed-Mode
    Windows Simulator with Schematic Capture,
    Waveform Display, FFT's and Filter Design.
  9. Presumably, the dart. They've been banned in the US for some time now.

    And bullets are definitely harder than the skull, even of innocent
    bystanders - every year, about cinco de Mayo in So Cal, there are
    news reports of kids killed by bullets fired into the air by idiots.

    Good Luck!
  10. Jasen Betts

    Jasen Betts Guest

    why do you suppose the electron current then flows to?

    This does not explain why the current measured is in the opposite direction
    to that which would normally be caused by the battery (V').

    It seems to me that if your hypothesis were to be true then the gas pressure
    would effect the spacing between the peaks, have you observed that ? and if
    not why not?

  11. Guest

    Thanks for the link! :)

    "The values of accelerating voltage where the current dropped gave a
    measure of the energy necessary to force an electron to an excited

    OK, trichel pulses may be called a "quantum effect" if one calls
    electron emission a quantum effect (I consider the particle behaviour
    of atoms and electrons to be "classical"). Anyway, I didn't get the
    impression that that was the issue.

  12. harry

    harry Guest

    OK it wasn't what it looked to me, this is much clearer.

    "The values of accelerating voltage where the current dropped gave a
    measure of the energy necessary to force an electron to an excited

    Thanks for the link! :)


  13. Ahmmm...

    The fact that atoms absorb and emit energy by electronics moving to
    different "orbits" in *discrete* steps is one of the fundamental corner
    stones of QM. The spectrum of the hydrogen atom was only explained by
    such quantisation.

    Kevin Aylward
    SuperSpice, a very affordable Mixed-Mode
    Windows Simulator with Schematic Capture,
    Waveform Display, FFT's and Filter Design.
  14. Harry

    Harry Guest

    Yes I agree, the ASCII plot looked like Trichel pulses but it wasn't that at

Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day