Question

There is a stationary point charge of +Q1 coulombs at origin. Stationary point charges are
kept at points on X axis at A(−1, 0), B(2, 0), C(x, 0). Charges at A : +Q, B : +3Q, C : +4Q
coulombs. The net resultant electrostatic force on charge at O due to charges at A, B, C is zero.
Calculate x

Answer 1

Answer:

work done = change in PE

PE 1 =

4πϵ

1

1

q

1

q

2

PE 2 =

4πϵ

1

2

q

1

q

2

work done =

4πϵ

1

q

1

q

2

(

1

1

−

2

1

)=−9mJ