Answer:
[tex]W=kq_1q_2(\dfrac{1}{x_1}-\dfrac{1}{\sqrt{x_2^2+y_2^2}})[/tex]
Explanation:
Position of charge q₁ is (0,0)
Position of charge q₂ is (x₁,0)
So, the electric potential energy between the charges is given by :
[tex]U_1=k\dfrac{q_1q_2}{x_1}[/tex]
Now the position of charge q₂ has been changes from (x₁,0) to (x₂,y₂). Now, electric potential energy between the charges is :
[tex]U_2=k\dfrac{q_1q_2}{\sqrt{x_2^2+y_2^2}}[/tex]
We know form the work energy theorem that, the change in potential energy is equal to the work done. Mathematically, it is given by :
[tex]W=-\Delta U[/tex]
[tex]W=-(U_2-U_1)[/tex]
[tex]W=(U_1-U_2)[/tex]
[tex]W=(k\dfrac{q_1q_2}{x_1}-k\dfrac{q_1q_2}{\sqrt{x_2^2+y_2^2}})[/tex]
[tex]W=kq_1q_2(\dfrac{1}{x_1}-\dfrac{1}{\sqrt{x_2^2+y_2^2}})[/tex]
Hence, the work done by the electrostatic force on the moving point charge is [tex]kq_1q_2(\dfrac{1}{x_1}-\dfrac{1}{\sqrt{x_2^2+y_2^2}})[/tex]. Hence, this is the required solution.