Two charges, each equal to q, aer kept at `x=-a` and `x=a` on the x-axis. A particle of mass m and charge `q_0=q/2` is placed at the origin. If charge `q_0` is given a small displacement (ylt lt a) along the y-axis, the net force acting on the particle is proportional to

Options

A. y
B. `-y`
C. `1/y`
D. `-1/y`

Answer

A

Explanation

Net force`=2F sin theta=2[(kqq_(0))/((a^(2)+y^(2)))].y/((a^(2)+y^(2))^(.^(1)//_(2)))`

`=(2kqq_(0))/((a^(2)+y^(2))^(.^(3)//_(2)))~~(2kqq_(0)y)/a^(3) prop y`