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The volume of metallic cylindrical (hollow) pipe of uniform thickness is 748 c.c. Its length is 14 cm and its external radius is 9 cm. The thickness of the pipe is
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- 0.5 cm
- 1.5 cm
- 1 cm
- 2 cm
- 0.5 cm
Correct Option: C
Let the internal radius of pipe be r cm.
External radius = R cm = 9 cm.
∴ Volume of the material of pipe = π(R² - r²)h
| ⇒ | (9² - r²) × 14 = 784 | |
| 7 |
| ⇒(81 - r²) = | = 17 | |
| 22 × 14 |
⇒ r² = 81 – 17 = 64
⇒ r = 64 = 8 cm
∴ Thickness of pipe = 9 – 8 = 1 cm.
