A) \[\frac{{{r}_{A}}}{{{r}_{B}}}\]
B) \[\frac{{{r}_{B}}}{{{r}_{A}}}\]
C) \[\frac{{{r}_{A}}}{{{r}^{2}}_{B}}\]
D) \[\frac{{{r}_{B}}}{{{r}^{2}}_{A}}\]
Correct Answer: B
Solution :
\[\frac{4\pi }{3}{{r}^{3}}\rho c\left( -\frac{dT}{dt} \right)=\sigma 4\pi {{r}^{2}}({{T}^{4}}-T_{0}^{4})\] \[\therefore \] \[\left( -\frac{dT}{dt} \right)=\frac{3\sigma }{\rho rc}({{T}^{4}}-T_{0}^{4})=H\](say) Ratio of rates of fall of temperature\[\frac{{{H}_{A}}}{{{H}_{B}}}=\frac{{{r}_{B}}}{{{r}_{A}}}\]You need to login to perform this action.
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