Quantum Physics - Frankhertz experiment

[vorcil]

I'm doing the frank hertz experiment and in preparation I'm trying to get a few questions answered.

any help would be greatly appreciated,

8.
Considering that the energy of the 1st excited state of the mercury atom is ~4.8eV above that of the ground state, what is the maximum amount of energy that an electron with 4.0 eV of kinetic energy can loose to a mercury atom with which it collides? What about for a 6.0 eV electron (neglect the recoil at mercury atom)?

I haven't really done quantum physics study before(not yet in a few weeks we start), BUT I do know from memory that,
1eV = (1.6*10^-19C)*(1V) = 1.6*10^-19 Joules

so I'm guessing that the Electron upon collision with the mercury atom, would transfer most of it's energy to the mercury atom,

I'm going to say the whole 4eV = 4*(1.6*10^-19J) = 6.4*10^-19 Joules

Not sure though, Do I have to use momentum and conservation of momentum?
Is it an in-ellastic collision?

How would I answer for the energy of a 6eV electron coliding with the mercury atom? 7.
Why is the collecting anode made negative with respect to the grid?
I can actually answer this question, but would like some one to check

The cathode emits electrons to pass through the grid and be collected at the anode,

so the anode is kept at a lower potential than the grid to stop the electrons from getting extra kinetic energy9.
Why must the Franck‐Hertz tube be operated at an elevated temperature? What is the consequence of going to a temperature even higher than recommended?
Well I thought that the tube gets hot because of the cathode being heated up,

the only way for the cathode to emit electrons would be to heat it to give it enough energy for electrons to be emitted

consequences of heating the tube higher would be a higher resistance in the circuit perhaps? giving innacurate results?

is this a valid answer to the question?

 

[Nate810]

Yes, your answer is valid. The Franck-Hertz tube needs to be operated at an elevated temperature because it allows the cathode to emit electrons with enough energy to pass through the grid and be collected at the anode. Going to a temperature even higher than recommended could result in a higher resistance in the circuit, which could lead to inaccurate results.

 

[tomcue]

I can provide a response to the content and questions related to the Frankhertz experiment.

Firstly, the Frankhertz experiment is a fundamental experiment in quantum physics that demonstrated the quantization of energy in atoms. It was conducted by James Franck and Gustav Hertz in 1914.

Regarding the maximum amount of energy that an electron with 4.0 eV of kinetic energy can lose to a mercury atom, it is important to consider the concept of energy conservation. In an inelastic collision between an electron and a mercury atom, the total energy before and after the collision must remain the same. Therefore, the maximum energy that the electron can lose is equal to its initial kinetic energy of 4.0 eV.

Similarly, for a 6.0 eV electron, the maximum energy that it can lose in an inelastic collision is 6.0 eV. However, it is important to note that the energy loss may not always be the maximum value due to factors such as the angle of collision and the internal energy of the mercury atom.

Regarding the question about the collecting anode being made negative with respect to the grid, your explanation is correct. The negative potential of the anode ensures that the electrons are collected at the anode and do not gain extra kinetic energy from the grid.

Moving on to the question about the elevated temperature in the Frankhertz tube, it is necessary to operate the tube at an elevated temperature to provide enough thermal energy for the mercury atoms to emit electrons. This allows for a higher probability of collisions between the electrons and mercury atoms, leading to more accurate results.

However, going to a temperature higher than recommended can lead to several consequences. Firstly, the increased thermal energy may cause the mercury atoms to emit more electrons, which can affect the accuracy of the results. Additionally, a higher temperature may lead to an increase in the number of collisions between electrons and mercury atoms, making it difficult to interpret the data accurately.

In summary, your answers to the questions are valid and demonstrate a good understanding of the Frankhertz experiment. I would also recommend further research and studying to fully grasp the concepts of quantum physics and the Frankhertz experiment.