Calculating Electron Trajectory in an Electric Field

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SUMMARY

The discussion focuses on calculating the trajectory of an electron in an electric field, specifically when it is accelerated from a filament towards a metal grid at 180 Volts and subsequently towards a plate at -10.0 Volts. Key concepts include the work-energy theorem, where the work done on the electron is equal to the change in potential energy, and the relationship between kinetic energy (KE) and potential energy (PE). The work done is calculated as 3.04x10-17 Joules, indicating the point at which the electron's kinetic energy becomes zero and it stops moving towards the plate.

PREREQUISITES
  • Understanding of electric potential and electric fields
  • Familiarity with the work-energy theorem
  • Knowledge of kinetic energy and potential energy concepts
  • Basic calculus for evaluating integrals
NEXT STEPS
  • Study the work-energy theorem in detail
  • Learn about electric fields and forces on charged particles
  • Explore the concept of potential difference in electric circuits
  • Investigate the conservation of energy in electric fields
USEFUL FOR

Physics students, electrical engineers, and anyone interested in understanding the motion of charged particles in electric fields.

rhettfraser
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Homework Statement


An electron is accelerated from the filament in a vacuum tube towards a metal grid which is maintained at a potential of 180 Volts. It goes through one of the holes in the grid and continues towards a metal plate 1.2 cm away which is maintained at a potential of -10.0 Volts.

How close to the plate does the electron get?


Homework Equations



Im not sure, maybe something to do with Potential Difference

The Attempt at a Solution



I don't know where to start
 
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Welcome to PF!

Hi rhettfraser! Welcome to PF! :smile:

Hint: work done = ∫ force"dot"distance = ∫ electric-field"dot"charge, and the electron will stop when the KE is zero. :wink:
 


tiny-tim said:
Hi rhettfraser! Welcome to PF! :smile:

Hint: work done = ∫ force"dot"distance = ∫ electric-field"dot"charge, and the electron will stop when the KE is zero. :wink:

thanks
 


tiny-tim said:
Hi rhettfraser! Welcome to PF! :smile:

Hint: work done = ∫ force"dot"distance = ∫ electric-field"dot"charge, and the electron will stop when the KE is zero. :wink:

but how do you find the force?
 
uhh? you don't, you use ∫ electric-field"dot"charge :smile:
 
tiny-tim said:
uhh? you don't, you use ∫ electric-field"dot"charge :smile:

ok now I've worked out that the work done is 3.04x10-17
how should i work out that when KE is zero the electron will stop?
I know that W= Change in PE, is there anyway that W is related to KE?
 
Conservation of energy … KE + PE = constant :smile:

(or work-energy theorem …KE + W = constant)
 

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