Find the electric potential energy

[Fatima Hasan]

Homework Statement

Homework Equations

##V= \frac {kq}{r}##
##V= \frac {U}{q}##

The Attempt at a Solution

##V= \frac {kq}{r}## = 9*10⁹*-5*10^-9 /0.1= -450 V
##U= \frac {V}{q}## = -450 * -2*10^-9 = 900nJ
Is my answer correct ?

 

[gneill]

Homework Statement

View attachment 223345

Homework Equations

##V= \frac {kq}{r}##
##V= \frac {U}{q}##

The Attempt at a Solution

##V= \frac {kq}{r}## = 9*10⁹*-5*10^-9 /0.1= -450 V
##U= \frac {V}{q}## = -450 * -2*10^-9 = 900nJ
Is my answer correct ?

Yes, but the form of your second relevant equation in your last line of calculations is not. Fortunately you did the actual calculation correctly anyways