Frank Hertz Experiment – geeksforjobs


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In this I very much want that the energy will be transferred from the electron in the atom, always in discrete values.


Organ filament, cathode, anode, grid-1. Grid-2


Frank-Hz tubes in this instrument from early spectroscopic work. It is clear that the radiation of an atom is emitted in discrete radiation v ‘e = hv’. Is related to the change in energy levels through. It should then be expected that the transfer of energy to the atomic electron must always occur by any mechanism. Discrete Amount. One such mechanism of energy transfer is through the tilt of a low energy electron. In 1916 Frank and Hertz set out to verify their idea.

1. It is possible to excite atoms by low energy electron bombardment.

2. Energy transferred from electrons to atoms always had discrete values.

3. The values ​​obtained for the energy level were in agreement with the spectroscopic results.

Thus the existence of the energy level put forward by the bore can be proved directly. This experiment is very important and can be performed in any challenge or university level bob.

The device consists of a Frank-Hertz tube, a tetrode filled with experimental material vapor, indicating the original scheme of the experiment.

The electron emitted by the filament can be accelerated by the potential between the cathode and the grid. Grids are wire mesh and allow electrons to pass through plate A with potential slightly negative with respect to the grid. This helps to create dips in voltage. As the voltage increases, the electron energy goes up and can therefore overcome the ability to reach the plate. This gives rise to a current in the ammeter that initially increases the voltage and electrons reach threshold values ​​to excite the atom to the previously allowed excited states. In doing so the electron loses energy and hence the number of electrons reaching the plate decreases. This decrease is proportional to the number of inletastic collisions that occurred. When it is further increased and reaches a value so that the excitation has potential. It is possible for an electron to excite an atom.

Halfway into the middle of the grid and lose all of its energy and gain enough energy to excite the atoms again and this leads to a second dip in the current. The advantage of this type of configuration of potentials is that the current becomes all the more pronounced and it is easier to achieve five times or even more multiplication in the first level excitation.

Make sure the electric current is 220k. Before power is turned on, make sure that all controls are at their minimum position and that the power has a current multiplier. Switch on the power. Turn all manuals to manual switches and check that the scanning voltage lob is at its minimum. Turn on the voltage display sectors and adjust the knob until the voltmeter reads 7.5.

Rotate the knob and observe the variation PF plate current with an increase of v. The current density will be maximum and minimally visible from time to time. The magnitude of the filament voltage and the value of the current multiplier.

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