Question

Moment of inertia of a uniform circular disc about a diameter is I. Its moment of inertia about an axis perpendicular to its plane and passing through a point on its rim will be

• A. 5 l
• B. 6 l
• C. 3 l
• D. 4 I

Answer 1

The correct option is B 6 l

Moment of inertia of disc about a diameter $=\frac{1}{4}M{R}^2=I$(given) $\therefore M{R}^2=4I$
Now moment of inertia of disc about an axis perpendicular to its plane and passing through a point on its rim
$=\frac{3}{2}M{R}^2=\frac{3}{2}\left(4I\right)=6I.$