Question

A charge of `2 C` is at the origin. How much energy would be applied to or released from a `-1 C` charge if it is moved from `(3 ,7)` to `(8,2 )`?

Answer 1

`Delta E~=-4,452*10^9 " J"`

Explanation:

`"distance between origin and the point(3,7) is:"`
`r_1=sqrt((3-0)^2+(7-0)^2)`
`r_1=sqrt 58`
`"distance between origin and the point (8,2) is:"`
`r_2=sqrt((8-0)^2+(2-0)^2)`
`r_2=sqrt 68`
`E_1=(k*2*(-1))/sqrt 58`
`E_1=(-2*9*10^9)/sqrt 58`
`E_1~=-2,362*10^9 " J"`
`E_2=(k*2*(-1))/sqrt 68`
`E_2=(-2*9*10^9)/sqrt 68`
`E_2~=-2,18*10^9 " J"`
`Delta E=E_2-E_1`
`Delta E=-2,18*10^9-2,362*10^-9`
`Delta E~=-4,452*10^9 " J"`