Chapter 20 - Electric Potential and Electric Potential Energy - Problems and Conceptual Exercises - Page 717: 6

$\Delta U=-25,500eV$

We know that $\Delta U=q_{\circ}\Delta V$ We plug in the known values to obtain: $\Delta U=(-e)(25,500)$ $\Delta U=-25,500eV$ $\Delta U=-25,500eV\times 1.6\times 10^{-19}\frac{J}{eV}$ $\Delta U=4.08\times 10^{-15}J$