An infinitely long line of charge has linear charge density 5.00×1012 C/m . A pr
ID: 1411190 • Letter: A
Question
An infinitely long line of charge has linear charge density 5.00×1012 C/m . A proton (mass 1.67×1027 kg, charge +1.60×1019 C) is 18.0 cm from the line and moving directly toward the line at 3.20×103 m/s . Part A Calculate the proton's initial kinetic energy. Express your answer with the appropriate units. Ki = 1.80•1021J SubmitMy AnswersGive Up Incorrect; Try Again; 5 attempts remaining Part B How close does the proton get to the line of charge? Express your answer with the appropriate units. d =
Explanation / Answer
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E=2k*lembda/r
Potential difference = dU = -Edr= -(2k*lembda/r)dr
Potential difference = U = -(2k*lembda)ln(r)
K.E of proton =0.5mv^2= 8.55*10^-21 J
A) The proton’s initial kinetic energy is 8.55*10^-21J
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Suppose proton stops at x m from line of charge
Work done by electric field = kinetic energy
work =qU=KE
r = d * e^(-mv^2 / (4kq)
r = 0.18 * e^(-(8.55*10^21 / (4 * (8.9875 * 10^9) * (5.00*10^12) * (1.602 * 10^-19))
r = 0.18 * e^(8.55^-21 /2.8836 * 10^-20)
r = 0.18 * e^(0.2965)
r = 0.242 m
0.242 m