chi tiết
Ta có
\(\begin{array}{l}{{\rm{W}}_{d1}} = \dfrac{1}{2}mv_1^2 = \left| e \right|{U_1}\\ \Rightarrow {U_1} = \dfrac{{\dfrac{1}{2}mv_1^2}}{{\left| e \right|}} \\= \dfrac{{\dfrac{1}{2}.9,{{1.10}^{ - 31}}.{{\left( {{{5.10}^7}} \right)}^2}}}{{\left| { - 1,{{6.10}^{ - 19}}} \right|}} = 7109,375V\end{array}\)
\(\begin{array}{l}{{\rm{W}}_{d2}} = \dfrac{1}{2}mv_2^2 = \dfrac{1}{2}m{({v_1} - \Delta v)^2} = \left| e \right|{U_1}\\ \Rightarrow {U_1} = \dfrac{{\dfrac{1}{2}m{{({v_1} - \Delta v)}^2}}}{{\left| e \right|}} \\= \dfrac{{\dfrac{1}{2}.9,{{1.10}^{ - 31}}.{{({{5.10}^7} - {{8.10}^6})}^2}}}{{\left| { - 1,{{6.10}^{ - 19}}} \right|}}\\ = 5016,375V\end{array}\)
\( \Rightarrow \Delta U = {U_2} - {U_1} \\= 7109,375 - 5016,375 = 2093V\)
