10th Class Mathematics Surface Areas and Volumes Question Bank Surface Area and Volume (Mensuration)

  • question_answer A hollow spherical shell is made of a metal of density \[4.9g/{{m}^{3}}\]. If it?s internal and external radii are 10 cm and 12 cm respectively, find the weight of the shell. (Take \[\pi =3.1416\])

    A)  5016 gm.                     

    B)  1416.8 gm.     

    C)  19948.27 gm.

    D)  5667.1 gm.

    Correct Answer: C

    Solution :

    (c): Volume of metal used \[=\frac{4\pi {{R}^{3}}}{3}-\frac{4\pi {{r}^{3}}}{3}\]\[=\frac{4\pi }{3}\left( {{12}^{3}}-{{10}^{3}} \right)=3050.66\,\,c{{m}^{3}}\] Weight = Volume \[\times \] density \[\Rightarrow \]   \[4.9\times 3050.66\] \[\Rightarrow \]   \[14948.27\,\,gm\]          

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