Question

A charge of `-2 C` is at the origin. How much energy would be applied to or released from a `4 C` charge if it is moved from `(7 ,5 )` to `(9 ,-2 )`?

Answer 1

`W=0,062 J`

Explanation:

`V=k*q/d" voltage of any charge on the any point "`
`V_A=k*q_1/sqrt 74 " potential of charge of -2C on the point(7,5)"`
`V_B=k*q_1/sqrt 85" potential of charge of -2C on the point(9,-2)"`
`V_(AB)=V_B-V_A`
`V_(AB)=k*q(1/sqrt 85-1/sqrt 74)`
`V_(AB)=k*q(sqrt 74-sqrt 85)/sqrt (74*85)`
`W=q*V_(AB)`
`"energy required for charge of 4C to move from(7,5) to (9,-2)"`
`W=4*k*q(sqrt 74-sqrt 85)/sqrt (74*85)`
`W=4*(-2)(sqrt 74-sqrt 85)/sqrt (74*85)`*
`W=-8*(8,602-9,219)/(79,31)`
`W=0,062 J`