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The diameter of a metallic sphere is 6 cm. The sphere is melted and drawn into a wire of uniform circular cross-section. If the length of the wire is 36 m, then what is its radius equal to ?

A) 0.1 cm
B) 0.01 cm
C) 0.001 cm
D) 1.0 cm

Correct Answer:

A) 0.1 cm

Description for Correct answer:
Radius of sphere = 3 cm

Now volume of sphere = \( \Large \frac{4}{3} \pi (3)^{3}\)

Now sphere is melted and draw into wire

Volume of sphere = Volume of cylinder formed

\( \Large \frac{4}{3} \pi (3)^{3} = \pi r^{2} \times 3600\)

\( \Large 36 \pi = r^{2} x 3600 \pi \)

\( \Large l = r^{2} x 100 \)

\( \Large r^{2} = \frac{1}{100} \)

\( \Large r = \frac{1}{10}cm = 0.1 cm \)

Option (A)is correct.

Part of solved CDS Maths(1) questions and answers : Exams >> CDSE >> CDS Maths(1)

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