A hollow metallic sphere has inner and outer radii, respectively as 5 cm and 10 cm if the mass of the sphere is 2.5 kg, find (a) density of the material, (b) relative density of the material of the sphere.

Explanation

Voluem of the material of the sphere is
`V=(4/5)pi(r_(3)^(2)-r_(1)^(3))`
`=4//3xx3.14x[(10/100)^(3)-(5/100)^(3)]`
`=4/3xx3.14xx[0.001-0.000125]`
`=4/3xx3.14xx0.00875 m^(3)=0.00367m^(3)`
a. Therefore, density of the material of the sphere is
`rho=M/V=2.5/0.00367kg//m^(3)=681.2 kg//m^(3)`
b. Relative density of the material of the sphere
`rho_(r)=681.2/1000=0.6812`