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The diameter of a sphere is 6 cm. It is melted and drawn into a wire of diameter 0.2 cm. Find the length of the wire.

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Question

The diameter of a sphere is 6 cm. It is melted and drawn into a wire of diameter 0.2 cm. Find the length of the wire. 

Sum
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Solution

Diameter of a sphere = 6 cm

Radius = 3 cm 

∴ Volume = `4/3pir^3`

= `4/3 xx 22/7 xx 3 xx 3 xx 3`

= `792/7 cm^3`    ...(i)  

Diameter of cylindrical wire = 0.2 cm  

Therefore, radius of wire =`0.2/2 = 0.1 = 1/10 cm ` 

Let length of wire = h 

∴ Volume = πr2h

= `22/7 xx 1/10 xx 1/10 xx h  cm^3`

= `(22h)/700  cm^3`  ...(ii) 

From (i) and (ii) 

`(22h)/700 = 792/7` 

`=> h = 792/7 xx 700/22` 

`=>` h = 3600 cm = 36 m 

Hence, length of the wire = 36 m

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Chapter 20: Cylinder, Cone and Sphere - Exercise 20 (G) [Page 316]

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Selina Concise Mathematics [English] Class 10 ICSE
Chapter 20 Cylinder, Cone and Sphere
Exercise 20 (G) | Q 5. | Page 316

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