A) 9 : 4
B) 2 : 3
C) 3 : 2
D) 4 : 9
Correct Answer: A
Solution :
Intensity of sound \[I=\frac{P}{4\pi {{r}^{2}}}\] or \[1\propto \frac{1}{{{r}^{2}}}\]or \[\frac{{{I}_{1}}}{{{I}_{2}}}={{\left( \frac{{{r}_{2}}}{{{r}_{1}}} \right)}^{2}}\] Here, \[{{r}_{1}}=2m,\,{{r}_{2}}=3\,m\] Substituting the values, we have\[\frac{{{I}_{2}}}{{{I}_{1}}}={{\left( \frac{3}{2} \right)}^{2}}=\frac{9}{4}\]You need to login to perform this action.
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