Four point charges `+q,+q,-q and -q` are placed on the corners of a square of side length 'a' as shown in the figure. The magnitude of electric field at a point which is at a distance `x (gt gt a)` from the centre along a line perpendicular to the plane of the square and passing through the centre is

Options

A. Moment of inertia of the system about `x` axis is `I_(x)=ma^(2)`
B. Moment of inertia of the system about `y` axis is `I_(y)=ma^(2)`
C. Moment of inertia of the systeme about the diagonal axis `AA' ` is `I_(AA')=ma^(2)`
D. Moment of inertia of the system about `z` axis is `I_(2)=ma^(2)`

Answer

A, B, C

Explanation

`I_(x x)=m((a)/(2))^(2)+m((a)/(2))^(2)+m((a)/(2))^(2)+m((a)/(2))^(2)=ma^(2)`
`I_(y y)=m((a)/(2))^(2)+m((a)/(2))^(2)+m((a)/(2))^(2)+m((a)/(2))^(2)=ma^(2)`
`I_(A A')=m((a)/(2))^(2)+m((a)/(2))^(2)+0+0=ma^(2)`
`I_(z z)=(m((a)/(2))^(2))xx4=2ma^(2)`