The square lamina of side 'b' has same mass as a disc of radius R. The M.I. of the two about an axis perpendicular to the plane and passing throught the centre are equal. The ratio b/R is

Options

A. 1
B. `sqrt(6)`
C. `sqrt(3)`
D. `1//3`

Answer

C

Explanation

`I=(M)/(12)(b^(2)+b^(2))`
`= (M)/(12)2b^(2)`
`therefore (MR^(2))/(2)=(M2b^(2))/(12)`
`therefore (b)/(R )= sqrt(3)`