`I` is moment of inertia of a thin circular ring about an axis perpendicular to the plane of ring and passing through its centre. The same ring is folded into `2` turns coil. The moment of inertia of circular coil about an axis perpendicular to the plane of coil and passing through its centre is

Options

A. `2I`
B. `4I`
C. `I/2`
D. `I/4`

Answer

D

Explanation

Mass is same, `l=2pirnrArrr alpha1/n` where `n` is number of turns
`Ipropr^(2)` and `(I_(1))/(I_(2))=((r_(1))/(r_(2)))^(2)=((n_(2))/(n_(1)))^(2)`