A sphere of radius R and made of material of relative density `sigma` has a concentric cavit of radius r. It just floats when placed in a tank full of water. The value of the ratio `R//r` will be

A sphere of radius R and made of material of relative density sigma has a concentric cavity of radius r. It just floats when placed in a tank full of water. The value of the ratio R//r will be

A sphere of radius R has a concentric spherical cavity of radius r. The relative density of the material of the sphere is sigma . It just floats when placed in tank full of water. The value of R/r is

A hollow sphere of radius R is made of a material of relative density rho . It will float if the thickness of its surface is

A sphere of material of relative density 8 has a concentric spherical cavity and just sinks in water.If the radius of the sphere is 2cm then the volume of the cavity is

A sphere of solid material of relative density 9 has a concentric spherical cavity and sinks in water. If te radius of the sphere be R. Then the radius of the cavity (r) will be related to R as

A sphere of radius R has a charge density sigma . The electric intensity at a point at a distance r from its centre is

A sphere of solid material of specific gravity 8 has a concentric spherical cavity and just sinks in water. The ratio of radius of cavity to that of outer radius of the sphere must be