a, U_{MN = \(\dfrac{A_{MN}}{q}=\dfrac{A_{M\infty}-A_{N\infty}}{q}=\dfrac{-q\dfrac{Q}{4\pi\varepsilon_0r_M}+q\dfrac{Q}{4\pi\varepsilon_0r_N}}{q}=-\dfrac{Q}{4\pi\varepsilon_01}+\dfrac{Q}{4\pi\varepsilon_02}=-\dfrac{Q}{8\pi\varepsilon_0}\)(V)}

_{b,\(A_{MN}=A_{M\infty}-A_{N\infty}=-A_{\infty M}-\left(-A_{\infty N}\right)=-q\dfrac{Q}{4\pi\varepsilon_0r_M}-\left(-q\dfrac{Q}{4\pi\varepsilon_0r_N}\right)=--q\dfrac{Q}{4\pi\varepsilon_01}+q\dfrac{Q}{4\pi\varepsilon_02}=-q\dfrac{Q}{4\pi\varepsilon_0}=\dfrac{1,6.10^{-29}}{\pi\varepsilon_0}\left(J\right)\)}

E= 1000 V/m
v_e= 3.10⁵ m/s

m_e= 9,1.10^-31 kg

q_e= -1,6.10^-19 C

A=ΔW⇔qEd=\(\dfrac{1}{2}\)m.v² - \(\dfrac{1}{2}\)m.\(v_0^2\)⇔−1,6.10−19.100.d=0− \(\dfrac{1}{2}\).9,1.10^-31.(3.10⁵)²⇔d=2,56.10−3m=2,56mm