We can calculate the electric potential energy of each individual charge using the following formula:
[tex]U=\frac{kQ}{r}[/tex]For the charge of 3.08 μC
[tex]U_{3.08}=\frac{(8.988\times10^9)(3.08\times10^{-6})}{(0.41)}=67476.27V[/tex]For the charge of -15.82 μ C:
[tex]U_{-15.82}=\frac{(8.988\times10^9)(-15.82\times10^{-6})}{(0.41)}=-346805.27V[/tex]For the charge of -3.61 μC:
[tex]U_{-3.61}=\frac{(8.988\times10^9)(-3.61\times10^{-6})}{(0.41)}=-79138.24V[/tex]And for the charge of 9.7 μC:
[tex]U_{9.7}=\frac{(8.988\times10^9)(9.7\times10^{-6})}{(0.41)}=212642.93V[/tex]Therefore, the electric potential at the center due to the the four charges is:
[tex]\begin{gathered} U=U_{3.08}+U_{-15.82}+U_{-3.61}+U_{9.7} \\ U=67476.27-346805.27-79138.24+212642.93 \\ U=-145824.31V \end{gathered}[/tex]Answer:
-145824.31 V