Find q for a moving particle


by Rae_4
Tags: electricity
Rae_4
Rae_4 is offline
#1
Jan29-13, 06:36 PM
P: 4
1. The problem statement, all variables and given/known data
A moving particle encounters an external electric field that decreases its kinetic energy from 8560 eV to 6770 eV as the particle moves from position A to position B. The electric potential at A is -50.5 V, and the electric potential at B is +25.9 V. Determine the charge of the particle. Include the algebraic sign (+ or −) with your answer.


2. Relevant equations
V=EPE/q, EPE=qEx=KE


3. The attempt at a solution
ΔKE/ΔV=q
1. The problem statement, all variables and given/known data



2. Relevant equations



3. The attempt at a solution
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gneill
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#2
Jan29-13, 07:20 PM
Mentor
P: 11,415
Quote Quote by Rae_4 View Post
1. The problem statement, all variables and given/known data
A moving particle encounters an external electric field that decreases its kinetic energy from 8560 eV to 6770 eV as the particle moves from position A to position B. The electric potential at A is -50.5 V, and the electric potential at B is +25.9 V. Determine the charge of the particle. Include the algebraic sign (+ or −) with your answer.


2. Relevant equations
V=EPE/q, EPE=qEx=KE


3. The attempt at a solution
ΔKE/ΔV=q
Hi Rae_4, Welcome to Physics Forums.

Did you have a particular question about the problem? You seem to be on the right track with your attempt.
Rae_4
Rae_4 is offline
#3
Jan29-13, 07:23 PM
P: 4
Yeah. I'm trying that formula, but it keeps telling me my answer is incorrect. I'm not sure what I'm doing wrong. When I attempt the practice version it is trying to tell me the answer is times 10^-18 and nothing I have in that formula would give me a number that small. Are my formulas incorrect?

haruspex
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#4
Jan29-13, 07:44 PM
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Find q for a moving particle


Quote Quote by Rae_4 View Post
nothing I have in that formula would give me a number that small. Are my formulas incorrect?
The energy is given in eV. The charge of an electron is 1.6021765 10 −19 coulomb. That's pretty small.
Rae_4
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#5
Jan29-13, 07:59 PM
P: 4
Figured it out. Thanks!


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