SSC Sample Paper Mock Test-6 SSC CGL Tear-II Paper-1

  • question_answer
    A solid metallic sphere of radius 8 cm is melted to form 64 equal small solid spheres. The ratio of the surface area of this sphere to that of a small sphere

    A)  4 : 1    

    B)                    1 :16

    C)  16 : 1

    D) 1 : 4

    Correct Answer: C

    Solution :

    Volume of the solid metallic Sphere \[=\frac{4}{3}\pi {{r}^{3}}=\frac{4}{3}\times \pi \times {{(8)}^{3}}=\frac{2048}{8}\pi \,\,c{{m}^{3}}\] Let the radius of the each small sphere = x cm \[\therefore \]      \[64\times \frac{4}{3}\pi {{x}^{3}}=\frac{2048}{3}\pi \] \[\Rightarrow \]               \[{{x}^{3}}=\frac{2048}{64\times 4}=8\] \[\Rightarrow \]               \[x=\sqrt[3]{8}=2\,\,cm\] \[\Rightarrow \] Required ratio \[=4\pi {{(8)}^{2}}:4\pi {{(2)}^{2}}=64:4=16:1\]                        


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