-
A hollow cylindrical tube 20 cm. long is made of iron and its external and internal diameters are 8 cm. and 6 cm. respectively. The volume (in cubic cm.) of iron used in making the tube is (Use π = 22/7)
-
- 1760
- 440
- 220
- 880
- 1760
Correct Option: B
Volume of used iron = π(R² – r²)h
where R = 4 cm; r = 3 cm.
| = | (4² – 3²) × 20 | |
| 7 |
| = | × (4 + 3)(4 – 3) × 20 | |
| 7 |
| = | × 7 × 20 = 440 cu.cm. | |
| 7 |
