What does Franck-Hertz experiment prove?
James Franck and Gustav Hertz conducted an experiment in 1914, which demonstrated the existence of excited states in mercury atoms. It confirms the prediction of quantum theory that electrons occupy only discrete, quantized energy states. This experiment supports Bohr model of atom.
What kind of collision occurs in between electrons and argon vapors in Frank-Hertz expt?
inelastic collision
Only those electrons with a critical value Vc1 hitting the argon atoms, transfer their energy and excite the argon atoms. During the process of inelastic collision they loss their kinetic energy, and unable to reach the anode resulting a significant drop in the current output after Vc1.
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 is the use of setting of VG1K at 1.5 volts and vg2a at 7.5 volts in Frank-Hertz experiment?
What is the use of setting VG1K at 1.5 volts? A.It is used to accelerate the electrons emitted from cathode towards anode.
Why electrons are used to excite atoms?
When an electron temporarily occupies an energy state greater than its ground state, it is in an excited state. An electron can become excited if it is given extra energy, such as if it absorbs a photon, or packet of light, or collides with a nearby atom or particle.
What is the highest energy level occupied by the electrons?
Valence electrons
Valence electrons are the electrons in the highest occupied principal energy level of an atom.
Can you explain the rising and fall of collected current in Frank Hertz experiment?
The Franck-Hertz Experiment Electrons are accelerated in the Franck-Hertz apparatus and the collected current rises with accelerated voltage. This drop is attributed to inelastic collisions between the accelerated electrons and atomic electrons in the mercury atoms.
Why argon is used in Franck-Hertz experiment?
The voltage difference between two consecutive valley point (or peak point) is the first excitation potential of argon atom. This experiment illustrates the fact that the slow electrons in Franck-Hertz tube collide with argon atoms, excite the atoms from low level to high level.
How does temperature affect the Franck-Hertz experiment?
The dependence of the Franck-Hertz curve on the tube temperature is explored, and we find a decrease in average peak spacing with increased temperature. Franck and Hertz’s original experiment included a window through which the wavelength of the emitted photons could be measured, which they found to be 2536 Å [2].
What are Bohr’s postulates?
Bohr’s model of the hydrogen atom is based on three postulates: (1) an electron moves around the nucleus in a circular orbit, (2) an electron’s angular momentum in the orbit is quantized, and (3) the change in an electron’s energy as it makes a quantum jump from one orbit to another is always accompanied by the …
Can a photon turn into an electron?
A photon can spontaneously degenerate into a particle with mass and its antiparticle in a process known as pair production. In this process, the energy of the photon is completely transformed into the mass of the two particles. For example, a photon can turn into an electron and an anti-electron.
What is the highest energy level that is completely filled?
neon has its highest energy level completely filled.
What was the result of the Franck Hertz experiment?
The Franck-Hertz Experiment: A Demonstration of Quantum Theory. The Franck-Hertz experiment, performed by James Franck and Gustav Hertz, was presented in 1914 and clearly demonstrated these discretised energy levels for the first time. It was a historic experiment, acknowledged by the 1925 Nobel Prize in Physics.
How is current obtained in Franck-Hertz schematic?
The schematic for the Franck-Hertz is similar. A beam of electrons is fired through a monatomic gas, and a current is measured. The electron beam is obtained by indirectly heating an oxide-coated cathode, and letting thermionic emission run its course.
What kind of apparatus is a Franck Hertz tube?
Mercury: The apparatus consists of a Franck-Hertz-Tube No. 6751 on a Front Panel No. 6753, in an oven No. 6752. The Franck-Hertz-Tube is a three-electrode tube with indirectly heated oxide-coated cathode, grid-form anode and collector electrode.
Why are the minima of the Franck-Hertz curve equally spaced?
It can be seen that the minima of the Franck-Hertz curves are equally spaced (barring experimental uncertainties). This spacing of the minima is equal to the excitation energy of the gas atoms (for mercury this is 4.9 eV).