Why is the grid used in Franck Hertz experiment?

Why is the grid used in Franck Hertz experiment?

The Frank-hertz tube in this instrument is a tetrode filled with the vapour of the experimental substance Fig. 1 indicates the basic scheme of experiment. The electrons emitted by filament can be accelerated by the potential VG2K between the cathode and the grid G2. The grid G1 helps in minimizing space charge effects.

What is grid in Franck Hertz experiment?

A contemporary Franck–Hertz tube is shown in the photograph. It is fitted with three electrodes: an electron-emitting, hot cathode; a metal mesh grid; and an anode. The grid’s voltage is positive relative to the cathode, so that electrons emitted from the hot cathode are drawn to it.

How many electrodes are used in Franck Hertz experiment?

three electrodes
Experimental Apparatus: The primary apparatus used in this experiment is a vacuum tube constructed with three electrodes (a triode) and containing a small drop of mercury. This tube is mounted inside a thermostatically controlled oven and can be viewed through the window on the backside of the oven.

What did Franck-Hertz experiment prove?

In 1914, James Franck and Gustav Hertz performed an experiment which demonstrated the existence of excited states in mercury atoms, helping to confirm the quantum theory which predicted that electrons occupied only discrete, quantized energy states.

What are the application of Franck-Hertz experiment?

Franck and Hertz decided to study electrons, atoms, and the transfer of kinetic energy. Their experiment extended the application of quantum theory to electrons and their energy levels, and provided a new technique for studying atomic structure.

What is Hertz experiment?

Hertz experiment consists of two metallic plates of equal size, placed 60 cm apart, held parallel to each other. Two small spheres S1 and S2 are placed closed to each other and connected to the plates A and B by thick metalic rods respectively. Using an induction coil the spheres are charged to high value.

What is the use of setting VG2A at 7.5 volts in Frank Hertz experiment?

What is the use of setting VG2A at 7.5 volts? A. This grid acts as a sort of retarding potential for the electrons if the electrons have more than 7.5 volts then they will pass and reach anode and we will get current otherwise they will return and then re-accelerate towards anode.

What did Franck Hertz do with past the grid?

Past the grid was a collection plate held at a small negative voltage with respect to the grid. The values of accelerating voltage where the current dropped gave a measure of the energy necessary to force an electron to an excited state. *Nobel Prize in physics, 1925

What was the purpose of the Franck-Hertz experiment?

Franck-Hertz Experiment. The Franck-Hertz Experiment*. In 1914, James Franck and Gustav Hertz performed an experiment which demonstrated the existence of excited states in mercury atoms, helping to confirm the quantum theory which predicted that electrons occupied only discrete, quantized energy states. Electrons were accelerated by

How is the Franck Hertz display for Mercury formed?

The Franck-Hertz display for mercury shown at left was formed by sweeping the accelerating voltage and recording current vs voltage on an oscilloscope in x-y mode. The measured separation of the peaks corresponds to the excitation energy of the involved mercury transition. Index Franck- Hertz Experiment HyperPhysics****Quantum Physics R Nave

How is current measured in the Franck Hertz tube?

Data collected using mercury vapour heated to 150 Celsius within the Franck-Hertz tube. Current is plotted as a function of accelerating voltage. Note that the general pattern is important and not the sharp jumps which are simply experimental noise.