Electrons flow in thermionic emmission?

  • Thread starter Thread starter captain-hawks
  • Start date Start date
  • Tags Tags
    Electrons Flow
AI Thread Summary
To achieve a continuous flow of electrons, a high positive potential and low gas pressure are essential. Electrons, being much lighter than air molecules, can be obstructed by them, necessitating a vacuum or low-pressure environment for effective flow. High positive potential attracts and accelerates electrons, facilitating current. In thermionic emission, heat provides energy that converts to kinetic energy, enabling electron movement. Understanding these principles is crucial for applications involving thermionic emission.
captain-hawks
Messages
1
Reaction score
0
Explain that to cause a continuous flow of elctrons requires high positive potential and less gass pressure?
Can anyone answer this please
 
Last edited by a moderator:
Physics news on Phys.org
Hi,
If you want electrons to flow, you need vacuum or gas at low pressure. this is because, electrons are extremely light, relative to air molecules. The air atoms or molecules stop them. The high positive potential attracts the electrons and accelerates them, causing a flow of current.
But why are you asking this under the title "thermionic emission"?
In thermionic emission, electrons gain energy due to heat. This energy is transformed into Kinetic energy, causing the electron flow.
 

Thread 'Maxwell stress tensor'

This is from Griffiths' Electrodynamics, 3rd edition, page 352. I am trying to calculate the divergence of the Maxwell stress tensor. The tensor is given as ##T_{ij} =\epsilon_0 (E_iE_j-\frac 1 2 \delta_{ij} E^2)+\frac 1 {\mu_0}(B_iB_j-\frac 1 2 \delta_{ij} B^2)##. To make things easier, I just want to focus on the part with the electrical field, i.e. I want to find the divergence of ##E_{ij}=E_iE_j-\frac 1 2 \delta_{ij}E^2##. In matrix form, this tensor should look like this...
View full post »
Thread 'Applying the Gauss (1835) formula for force between 2 parallel DC currents'

Thread 'Applying the Gauss (1835) formula for force between 2 parallel DC currents'

Please can anyone either:- (1) point me to a derivation of the perpendicular force (Fy) between two very long parallel wires carrying steady currents utilising the formula of Gauss for the force F along the line r between 2 charges? Or alternatively (2) point out where I have gone wrong in my method? I am having problems with calculating the direction and magnitude of the force as expected from modern (Biot-Savart-Maxwell-Lorentz) formula. Here is my method and results so far:- This...
View full post »

Similar threads

B Initiation and the math behind Arc Discharges
Replies
8
Views
1K
I Is the Poynting Vector Field the Only Factor in Energy Flow in Circuits?
Replies
16
Views
3K
How can electrons flow all the way through the circuit?
Replies
21
Views
3K
Thermionic emission and current density
Replies
25
Views
17K
Measurement of vacuum diode electron flow
Replies
29
Views
17K
Understanding the Flow of Electrons in AC Circuits
Replies
25
Views
3K
What Causes Induced EMF in Conductive Bars Moving Through Magnetic Fields?
Replies
20
Views
2K
Why does current choose the short circuit path?
Replies
18
Views
5K
Photoelectric Effect: Electron Flow Explained
Replies
5
Views
2K
Stupid question relating to electric induction
2
Replies
74
Views
14K

Hot Threads

Recent Insights

Back
Top