The volume of a metallic cylindrical pipe is 7480 cm3. If its length is 1.4 m and its external radius is 9 cm, then its thickness (given π = 22/7) is:
Show answer & explanation
Correct answer: D
Explanation
Correct Answer is option 4 i.e. 1 cm
|
Concept |
Understanding |
Application |
|
Volume of hollow cylinder = π(r12 – r22)h |
Given: r1 = 9 cm, h = 1.4 m = 140 cm Volume of cylinder = 7480 cm3 |
Volume of cylinder: 22/7 × (92 – r22) × 140 = 7480 ⇒ (81 – r22) = 748/44 ⇒ 81 – r22 = 17 ⇒ r2 = √64 = 8 cm Required thickness of cylinder = r1 - r2 = 9 – 8 = 1 cm |