Answer:
So the change will be express as a difference of both electric potential:
[tex]\Delta U = U_{2}-U_{1}=1.011*10^{-6} J[/tex]
Explanation:
The electric potential is given by:
[tex]U=k\frac{q_{1}q_{2}}{r}[/tex]
The electric potential at a distance of 2.3 cm will be:
[tex]U_{1}=9*10^{9}\frac{1.2*10^{-9}2.8*10^{-9}}{0.023}[/tex]
[tex]U_{1}=9*10^{9}\frac{1.2*10^{-9}2.8*10^{-9}}{0.023}[/tex]
[tex]U_{1}=1.315*10^{-6}J[/tex]
Now, the electric potential when the first particle has moved 1.0 cm is.
Here, the distance between the two particles will be 2.3 cm - 1 cm = 1.3 cm
[tex]U_{2}=9*10^{9}\frac{1.2*10^{-9}2.8*10^{-9}}{0.013}[/tex]
[tex]U_{2}=9*10^{9}\frac{1.2*10^{-9}2.8*10^{-9}}{0.013}[/tex]
[tex]U_{2}=2.326*10^{-6} J[/tex]
So the change will be express as a difference of both electric potential:
[tex]\Delta U = U_{2}-U_{1}=1.011*10^{-6} J[/tex]
I hope it helps you!