The ratio of the radii of gyration of a circular disc to that of circular ring, each of same mass and same radius about their axes is

Options

A. `sqrt(3) : sqrt(2)`
B. `1 : sqrt(2)`
C. `sqrt(2) : 1`
D. `sqrt(2) : sqrt(3)`

Answer

b

Explanation

`(1_(1))/(1_(2)) = (MK_(1)^(2))/(MK_(2)^(2)) = ((1)/(2) MR^(2))/(MR^(2)) = (1)/(2)`
`therefore" "(K_(1))/(K_(2)) = (1)/(sqrt(2)) = 1 : sqrt(2)`