As per this diagram a point charge `+q` is placed at the origin `O`. Work done in taking another point charge `-Q` from the point `A(0, a)` to another point `B(a, 0)` along the staight path `AB` is:

Options

A. zero
B. `((-qQ)/(4 pi epsilon_(0)a^(2)))sqrt(2) a`
C. `((-qQ)/(4 pi epsilon_(0)a^(2))) (a)/(sqrt(2))`
D. `((qQ)/(4 pi epsilon_(0)a^(2)))sqrt(2) a`

Answer

1

Explanation

`V_(A) = (1)/(4 pi in_(0)) .(q)/(a) , V_(B) = (1)/(4 pi in_(0)) .(q)/(a)`
`W_(A rarr B) = -Q(V_(B) - V_(A)) = 0`