A) 14.14 second
B) 20 seconds
C) 18.30 second
D) 40 seconds
Correct Answer: D
Solution :
Solidification time for a sphere, \[t\,\alpha \,{{\left( \frac{V}{A} \right)}^{2}}\] \[\frac{V}{A}=\frac{\left( \frac{4}{3}\,\pi {{r}^{3}} \right)}{4\pi {{r}^{2}}}=\frac{r}{3}\] \[t\propto {{r}^{2}}\] \[\frac{{{t}_{2}}}{{{t}_{1}}}={{\left( \frac{4}{3} \right)}^{2}}=4\] \[{{t}_{2}}=4\times 10=40\,s\]You need to login to perform this action.
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