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An iron sphere of radius 27 cm is melted to form a wire of length 729 cm. The radius of wire is
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- 6 cm
- 9 cm
- 18 cm
- 36 cm
- 6 cm
Correct Option: A
| Volume of iron sphere = | πr³ | |
| 3 |
| Volume of metallic sphere = | × π × 27 × 27 × 27 | |
| 3 |
= (36 × 27 × 27)π cu. cm.
∴ If the radius of wire be R cm., then π × R² × 729 = 36 × 27 × 27π [∵ V = πR²H]
| ⇒ R² = | = 36 | |
| 729 |
∴ R = 36 = 6 cm.
