The ratio of moment of inertia about axis of a ring to a axis of disc of same mass and radius is …………….

Options

A. `1:1`
B. `2:1`
C. `4:1`
D. `1:2`

Answer

B

Explanation

The moment of inertia ring about an axis passing through its centre and perpendicular to its plane is `I_("ring")=MR^(2)`. Where M = mass R = Radius.
Moment of inertia disc about on axis passing through its center and perpendicular to its plane
`I_("disc")=(1)/(2)MR^(2)`
`therefore (I_("ring"))/(I_("disc"))=(MR^(2))/((1)/(2)MR^(2))=2:11`