2013 · Q67
A cylindrical tube open at both ends is made of metal. The internal diameter of the tube is 6 cm and length of the tube is 10 cm. If the thickness of the metal used is 1 cm, then the outer curved surface area of the tube is
Elementary MathematicsMensuration
- A140π sq cm
- B146.5π sq cm
- C70π sq cm
- DNone of the above
Explanation
Outer R=4; 2π×4×10=80π, not listed → None. Verified via allen.in (internal dia 6 cm). Answer D.