2021 · Q32
A solid sphere of diameter 60 mm is melted to stretch into a wire of length 144 cm. What is the diameter of the wire?
Elementary MathematicsMensuration
- A0.5 cm
- B1 cm
- C1.5 cm
- D2 cm
Explanation
The sphere (radius 3 cm) has volume (4/3)π·27 = 36π cm³. As a wire of length 144 cm: πr²·144 = 36π gives r² = 1/4, so r = 0.5 cm and the diameter is 1 cm. Hence option B.