A) 1
B) 2
C) 0.5
D) 1.5
Correct Answer: A
Solution :
[a] Let, the radius of hollow shpere = r cm. Then, according to the questions, \[\frac{4}{3}\pi ({{9}^{3}}-{{r}^{3}})=\frac{4}{3}\pi \,{{(1)}^{3}}+\frac{4}{3}\pi \,{{(6)}^{3}}\] \[\Rightarrow \] \[{{9}^{3}}-{{r}^{3}}=1+{{6}^{3}}\]\[\Rightarrow \]\[{{r}^{3}}={{9}^{3}}-{{6}^{3}}-1\] \[\Rightarrow \] \[{{r}^{3}}=729-216-1\]\[\Rightarrow \]\[513-1\] \[\Rightarrow \] \[{{r}^{3}}=512\]\[\therefore \]\[r=8\,cm\] Then, required thickness of sphere \[=9-8=1\,cm\] |
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