The radius of gyration of a solid shapere of radius r about a certain axis is r. The distance of this axis from the centre of the shpere is

Options

A. r
B. 0.5r
C. `sqrt0.6 r`
D. `sqrt0.4 r`

Answer

C

Explanation

k=r
`I= mr^(2) = (2)/(5) mr^(2) + md^(2)`
`rArr r^(2)- (2)/(5) r^(2)= d^(2) rArr d^(2)= (3r^(2))/(5)`
`rArr d= sqrt0.6 r`