A solid sphere of diameter 6 cm is melted and then cast into cylindrical wire of radius 0.3 cm. Find the length of the wire.

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  1. 4 m
  2. 65 cm
  3. 50 cm
  4. 3 m

Answer (Detailed Solution Below)

Option 1 : 4 m
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Detailed Solution

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Given:

Diameter of the solid sphere = 6 cm

Radius of the solid sphere (r) = 6 cm / 2 = 3 cm

Radius of the cylindrical wire (R) = 0.3 cm

Formula used:

Volume of sphere = (4/3)πr3

Volume of cylinder = πR2h

Volume of sphere = Volume of cylinder

Calculation:

Volume of sphere = (4/3)π(3)3

⇒ Volume of sphere = (4/3)π(27) = 36π cm3

Volume of cylinder = π(0.3)2h

⇒ 36π = π(0.09)h

⇒ h = 36 / 0.09 = 400 cm

⇒ h = 4 m

∴ The correct answer is option (1).

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