Twenty seven solid iron spheres, each of radius r and surface area S are melted toform a sphere with surface area `\ Sprimedot`Find the(i) radius `rprime`of the new sphere, (ii) ratio of `S a n d Sprimedot`

Explanation

(i)Here, Volume of 27 solid iron spheres = Volume of new sphere

So, `27**4/3**pi**r^3 = 4/3**pi**r'^3`

`=>27r^3 = r'^3`

`=>r'= 3r`


(ii)Now, `S' = 4pir'^2`

`=>S' = 4pi(3r)^2=9(4pir^2) = 9S`

`=>S/S'= 1/9`

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