How Far Does an Electron Travel Before Returning in an Electric Field?

[Zarrey]

Homework Statement

A very long, thin straight line of charge has a constant charge density of 2.0 pC/cm. An electron is initially 1.0 cm from the line and moving away ( that is, perpendicular to the line ) with a speed of 1000 km/s. How far does the electron go before it comes back?


i can't seem to find the required equations in my textbook. any help would be great.

 

[tiny-tim]

Hi Zarrey!

A very long, thin straight line of charge has a constant charge density of 2.0 pC/cm. An electron is initially 1.0 cm from the line and moving away ( that is, perpendicular to the line ) with a speed of 1000 km/s. How far does the electron go before it comes back?

Use conservation of energy.

(same for your other thread)

 

[Zarrey]

wow lol. i can't believe i didnt know that. thank you for reminding me :D

 

[Zarrey]

Conservation of energy is different when dealing with electrons it seems. is mass relevant?

 

[nasu]

First, you need to find the field around the line of charge as a function of distance. Gauss' theorem wil do nicely do to the symmetry.
Then you can use the work-energy theorem.

 

[tiny-tim]

Conservation of energy is different when dealing with electrons it seems.

no

is mass relevant?

mass always comes into the KE formula

mass is also relevant if it comes into the PE formula