From a uniform wire, two circular loops are made (`i`) `P` of radius `r` and (`ii`) `Q` of radius `nr`. If the moment of inertia of `Q` about an axis passing through its center and perpendicular to tis plane is `8` times that of `P` about a similar axis, the value of `n` is (diameter of the wire is very much smaller than `r` or `nr`)

Options

A. `8`
B. `6`
C. `4`
D. `2`

Answer

D

Explanation

Moment of inertia `P=Mr^(2)`
Moment of inertia `Q=(nM)(nr^(2))`
given `I_(Q)=8I_(P)rArrn=2`