Question

Question #70bb8

Answer 1

So option (1) is correct

Explanation:

It is obvious from the given figure that three charge points are situated at thrre vertices of an isosceles triangle in which two equal sides of length `l` is inclined at an angle `120^@` and `-2q` charge resides at the point of intersection of these two sides. So each of the other two angles of the isosceles triangle will be `30^@` .The c.g of two `+q` charge will be at the mid point of the line segment joining other two vertices of the triangle and the distance of resultatant `+2q` charge at this middle point from `-2q` charge will be `d=lxxsin30^@=l/2`

Hence the dipolemoment of the system is given by

`mu=2qxxd=2qxxl/2=ql`