Question 63

A metallic sphere of radius 4 cm is melted and the cast into small spherical balls, each of diameter 0.4 cm. The number of small balls will be:

Solution

Volume of sphere = $$\frac{4}{3}\pi r^3$$

Let $$n$$ small balls will be formed, thus

=> $$n\times\frac{4}{3}\pi r^3=\frac{4}{3}\pi R^3$$

=> $$n\times(0.2)^3=(4)^3$$

=> $$n=\frac{64}{8}\times1000=8000$$

=> Ans - (B)

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