Six charges of equal magnitude, three positive and three negative, are to be placed on PQRSTU corners of a regular hexagon, such that field at the center is double that of what it would have been if only one positive charge is placed at R.

Options

A. `+,-,+,-,-,+`
B. `+,-,+,-,+,-`
C. `+,+,-,+,-,-`
D. `-,+,+,-,+,-`

Answer

D

Explanation

According to option (D) the electric field due to P and S and due to Q and T add to zero. While due to U and R will be added up. Hence, the correct option is (D)
(A) Common of forces along x-axis will vanish.
Net force along positive y-axis.
`E_(3)ltE_(1)ltE_(2)`

(B) Component of forces along y-axis will vanish. Net forced along positive x-axis.

(C) Component of forces along x-axis will vanish. Net force along negative y-axis.

(D) Component of forces along y-axis will vanish. Net force along negative x-axis.