Question

A charge of `-5 C` is at the origin. How much energy would be applied to or released from a `4 C` charge if it is moved from `(5 ,-3 )` to `(1 ,-2 )`?

Answer 1

`W~=213*10^9" J"`

Explanation:

`step-1:`
`"Potential at the point of (5,-3) created by charge of -5C:"`
`V_(<5,-3>)=-(k*5)/sqrt(5^2+3^2)=-(5k)/sqrt34`
`"Potential at the point of (1,-2) created by charge of -5C:"`
`V_(<1,-2>)=-(k*5)/sqrt(1^2+2^2)=-(5k)/sqrt 5`
`"work doing by electrical forces between two points:"`
`W=q(V_(<1,-2>)-V_(<5,-3>))`
`W=4(-(5k)/sqrt5+(5k)/sqrt34)`
`W=4*5*k(-sqrt5+sqrt34)/(sqrt5*sqrt34)`
`W=20k*(-2,236+5,831)/(13,038)`
`W=(71,9*k)/(13,038)" "k=9.10^9`
`W~=213*10^9" J"`