Solving Cross Section Confusion: Adding Positive and Negative Ions

Click For Summary
SUMMARY

The discussion focuses on resolving confusion regarding the addition of positive and negative ions in cross-sectional calculations. Participants emphasize that if the cross section does not appear in the relevant formula, it can be disregarded for the calculation. Additionally, they highlight the importance of considering the flux per unit area and the movement direction of charge carriers when determining the correct order of magnitude for the answer.

PREREQUISITES
  • Understanding of ion behavior in physics
  • Familiarity with flux concepts in electromagnetism
  • Knowledge of surface area calculations
  • Basic grasp of charge carrier dynamics
NEXT STEPS
  • Research the principles of ion transport in semiconductor physics
  • Learn about flux density and its applications in electromagnetism
  • Study the effects of charge carrier movement on electrical properties
  • Explore advanced surface area calculations in material science
USEFUL FOR

Students and professionals in physics, electrical engineering, and material science who are dealing with ion behavior and surface area calculations in their work.

arrozito
Messages
1
Reaction score
0
Homework Statement
A fluorescent tube with 3 cm diameter has a flux of positive and negative ions in it. That flux is
2x10^18 electrons by second and 0.5x10^18 positive ions (with charge +e) by second. What’s the current
inside the tube?

(sol 0,4A)
Relevant Equations
I = dq/dt = (delta)q/(delta)t = q/t
ik that i have to add the positive and negative ions but the cross section (surface) confuses me how do i resolve this?
 
Physics news on Phys.org
Hello arrozito, :welcome: !

arrozito said:
how do i resolve this
Well, since it does not occur in your relevant formula, perhaps you can forget about it ? Check what the answer is when you do (forget about it) !

Note: flux generally is per unit of area, but if the dimension of your given data doesn't have that, you may assume it is for the area of your device. Confusing, though !

Note 2: if you get a wrong answer of the right order of magnitude, consider the directions in which the charge carriers move: same or opposite ?
 
  • Like
Likes   Reactions: arrozito

Similar threads

  • · Replies 2 ·
Replies
2
Views
849
Replies
25
Views
3K
  • · Replies 10 ·
Replies
10
Views
2K
  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 10 ·
Replies
10
Views
2K
  • · Replies 12 ·
Replies
12
Views
1K
Replies
8
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
Replies
4
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K