An electron is ejected perpendicularly from the center of a wire of length 1 mm

Question

An electron is ejected perpendicularly from the center of a wire of length 1 mm with 10 eV of kinetic energy. If the electron travels 100 nm before stopping and starting to move back towards the wire. What is the line charge density on the wire? Hints: Total Energy = KE + PEelectric = Constant; there isn't enough information to use the gradient. When setting up the electric field use 0 as an endpoint of the line. Be careful about rounding when evaluating the voltage integral the difference is pretty small

Explanation / Answer

Potential energy is U = q*dV = (1.6*10^-19)*10*eV = 1.6*10^-19*10*1.6*10^-19 = 2.56*10^-37 J

potnetial at 100 nm is dV = lamda*ln(r)/(2*pi*eo)

10*1.6*10^-19 = (lamda*ln(100*10^-9)/(2*3.142*8.85*10^-12))

lamda = 0.3451*10^-12 F

lamda = 0.3451 pF

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.