Derivation of formula - electrons in an electric field

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Homework Help Overview

The discussion revolves around deriving a formula related to the angle between an electron beam and the plates in a Teltron tube, specifically focusing on the relationship expressed by the equation tan θ = Eqsh / mvh2.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss the need for defining variables involved in the equation and question whether both electric and magnetic fields are present. There is an exploration of the relationship between the components of the equation and the physical setup of the Teltron tube.

Discussion Status

Some participants have provided clarifications on the variables and their meanings, while others have suggested methods to calculate time of flight and forces involved. There appears to be a productive exchange of ideas, though no consensus on the complete derivation has been reached.

Contextual Notes

Participants note that the problem is constrained to an electric field only, and there is a request for more information to fully understand the derivation process.

synthesized
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I need to derive the following formula, in relation to the angle between the electron beam and the plates where the beam of electrons hits the plates in a Teltron tube:

[tex]tan \theta = \frac{Eqs_{h}}{mv_{h} ^2}[/tex]

I think I managed to complete about 70% of this, but I need to found out what it is in its entirety!
 
Last edited:
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synthesized said:
I need to derive the following formula, in relation to the angle between the electron beam and the plates where the beam of electrons hits the plates in a Teltron tube:

[tex]tan \theta = \frac{Eqs_{h}}{mv_{h} ^2}[/tex]

I think I managed to complete about 70% of this, but I need to found out what it is in its entirety!

I think we need more information here. Define the variables. Are there both electric and magnetic fields involved in this? Is this something like what you have?

http://www.telatomic.com/ttubes4.html
 
Last edited by a moderator:
yeah, that is pretty much the teltron tube I'm referring to. This is only an electric field.

in the eqn:
- theta = the angle between the plates (where the stream of electrons hits) and the electron gun (see attached pic)
- E = size of the electric field between the plates
- q = charge of the electron
- s = the horizontal (x) displacement between the electron gun and where the electron stream hits the plates.
- m = mass of the electron
- v = horizontal velocity of the electrons in the electron stream
 

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synthesized said:
yeah, that is pretty much the teltron tube I'm referring to. This is only an electric field.

in the eqn:
- theta = the angle between the plates (where the stream of electrons hits) and the electron gun (see attached pic)
- E = size of the electric field between the plates
- q = charge of the electron
- s = the horizontal (x) displacement between the electron gun and where the electron stream hits the plates.
- m = mass of the electron
- v = horizontal velocity of the electrons in the electron stream

Now we can help :smile: Given v and s you can calculate the time of flight, t, through the electric field. From E and q you can calculate the force, F, on the charge. From F and m you can calculate the acceleration, a, toward the positive plate. From a and t you can calculate the velocity component, u, perpendicular to the plate at the moment of impact. [tex]tan \theta[/tex] is the ratio of the two velocity components, u and v.
 
Thanks Dan :smile:
 

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