2021 · Q68
A hollow spherical shell is made of a metal of density 7 g/cm³. If its internal and external radii are 3 cm and 6 cm respectively, then what is the mass of the shell ? (take π = 22/7)
Elementary MathematicsMensuration
- A2772 g
- B3322 g
- C4433 g
- D5544 g
Explanation
Metal volume = (4/3)π(6³ − 3³) = (4/3)π·189 = 252π = 252 × 22/7 = 792 cm³. Mass = volume × density = 792 × 7 = 5544 g. This is option (d).