The excited mercury atom does not hit any metal plate. They bombarded a mercury atom vapor with electrons, and showed that the electrons lost energy only at discrete levels (corresponding to the energy needed to exite the mercury atoms). See this (pretty good) wikipedia article:Helphelphelp said:Hi
In the FH experiment, what is physically happening when the excited mercury atom hits the metal plate? why does it induce a current drop?
Thank you for any help :)
Helphelphelp said:In the FH experiment, what is physically happening when the excited mercury atom hits the metal plate? why does it induce a current drop?
The Franck-Hertz experiment is a classic physics experiment that demonstrates the energy quantization of atoms. It involves passing electrons through a tube filled with a low-pressure gas and measuring the current as the electrons are accelerated by a voltage. The current drops at specific voltages, indicating that the electrons are losing energy and exciting the gas atoms.
The current drop in the Franck-Hertz experiment is caused by inelastic collisions between the electrons and the gas atoms. When the electrons have enough energy, they can excite the gas atoms to higher energy levels. This results in a decrease in the number of electrons that can reach the anode, causing a drop in current.
The current drop in the Franck-Hertz experiment is significant because it provides evidence for the quantization of energy in atoms. This experiment helped to confirm the Bohr model of the atom and the concept of discrete energy levels. It also paved the way for further research into quantum mechanics and the understanding of atomic structure.
The voltage in the Franck-Hertz experiment affects the current by accelerating the electrons towards the anode. As the voltage increases, the electrons gain more energy and are able to excite the gas atoms to higher energy levels. This results in the current dropping at specific voltages corresponding to the energy difference between the different energy levels of the gas atoms.
Aside from voltage, other factors that can affect the current in the Franck-Hertz experiment include the type of gas used, the pressure of the gas, and the distance between the cathode and anode. These variables can alter the energy levels of the gas atoms and therefore affect the energy required for the electrons to excite them. Additionally, the temperature of the gas and the presence of impurities can also impact the current drop in the experiment.