Question
Download Solution PDFA spherical metal of radius 10 cm is molten and made into 1000 smaller spheres of equal sizes. In this process the surface area of the metal is increased by:
- 1000 times
- 100 times
- 9 times
- No change
Answer (Detailed Solution Below)
Option 3 : 9 times
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Detailed Solution
Download Solution PDFFormula Used:
Volume of sphere = \(\frac{4}{3}\)πr3
Surface area of sphere = 4πr2
Calculation:
If the radius of a smaller sphere be 'r cm' then
Acoording to the question:
\(\frac{4}{3}\)π(10)3 = 1000\(\frac{4}{3}\)π(r)3
r = 1 cm
Surface area of the larger sphere = 4π(10)2 = 400π
Total surface area of 1000 smaller spheres = 1000 × 4π(1)2 = 4000π
Net increase in the surface area = 4000π − 400π = 3600π
Hence, surface area of the metal is increased by 9 times.
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