Q: A circular disc X of radius R is made from an iron plate of thickness t and another disc Y of radius 4R is made from an iron plate of thickness t/4. Then, the relation between the moment of inertia I_{X} and I_{Y} is

(a) I_{Y} = 32 I_{X}

(b) I_{Y} = 16 I_{X}

(c) I_{Y} = I_{X}

(d) I_{Y} = 64 I_{X}

Ans: (d)