2021 · Q40
A hollow spherical shell is made up to a metal of density 3 g/cm³. If the internal and external radii are 5 cm and 6 cm respectively, then what is the mass of the shell? (Take π = 22/7)
Elementary MathematicsMensuration
- A1144 g
- B1024 g
- C840 g
- D570 g
Explanation
Shell volume = (4/3)π(6³ − 5³) = (4/3)π·91 cm³. Mass = density × volume = 3·(4/3)π·91 = 4π·91 = 4·(22/7)·91 = 1144 g. Hence option A.