Determing the kinetic energy of an electron

AI Thread Summary
The discussion centers on calculating the kinetic energy (KE) of an electron in an electric field, using the equation KEi + PEi = KEf. The initial kinetic energy is given as 2.4 x 10^-19 J, and after accounting for the potential energy change due to a 1 V potential difference, the final kinetic energy is calculated to be 4.002 x 10^-19 J. However, it is clarified that the electron is repelled by the negative plate, resulting in a decrease in kinetic energy as it moves. The conversation also suggests that it may be more straightforward to work in electron volts (eV) for such problems. The thread emphasizes the importance of understanding the effects of electric fields on electron motion.
Turion
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Homework Statement



sxvTCH3.png


Homework Equations


The Attempt at a Solution



KEi + PEi = KEf
2.4 x 10-19 + e(1) = KEf
KEf = 4.002 x 10-19 J

So option c would be correct, right? Thank you in advance.
 
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This one is a trick question, right? It would need 0 kinetic energy because the electric field itself would move the electron to the left until it reaches point C.
 
This one doesn't even make sense to me. How can the electron go back to plate D if plate D has the higher voltage?

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Turion said:

Homework Statement



sxvTCH3.png


Homework Equations





The Attempt at a Solution



KEi + PEi = KEf
2.4 x 10-19 + e(1) = KEf
KEf = 4.002 x 10-19 J

So option c would be correct, right? Thank you in advance.

No. The electron is repelled by the negative plate so its KE decreases when it moves from B to A.
And it's easier if you work in eV directly.
The potential difference between B and A is 1 V so the change in potential energy is 1eV.

And I think you are supposed to post one problem per topic.
 
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