Four identical rods, each of mass m and length l, are joined to form a rigid square frame. The frame lies in the X-Y plane with centre at the origin. The moment of inertia of the system about Z-axis is

Options

A. `(2ml^2)/3`
B. `(4ml^2)/3`
C. `(3ml^2)/5`
D. `(5ml^2)/7`

Answer

B

Explanation

`I= I_G + Md^2` where d =l/2
`I=[(ml^2)/12+(ml^2)/4]xx4" or " I=(4ml^2xx4)/12 =(4ml^2)/3`