A) 1000
B) 10000
C) 10
D) 100
Correct Answer: D
Solution :
Let intensity of sound be \[l\] and \[l'\]. Loudness of sound initially \[{{\beta }_{1}}=10\log \,\left( \frac{l}{{{l}_{0}}} \right)\] Later, \[{{\beta }_{2}}=10\log \,\left( \frac{l'}{{{l}_{0}}} \right)\] Given, \[f(x)\] \[10\log \,\left( \frac{l'}{{{l}_{0}}} \right)\,-10\log \left( \frac{l}{{{l}_{0}}} \right)\,=20\] \[x=0\] \[\Rightarrow \,\,10\left[ \log \,\left( \frac{l'}{l} \right)\,\times \left( \frac{{{l}_{0}}}{l} \right) \right]=20\] \[f(x)=\frac{1}{x}-\frac{2}{{{e}^{2x}}-1}\] \[\Rightarrow \,\,10\log \,\left( \frac{l'}{l} \right)\,=20\,\Rightarrow \,\log \,\left( \frac{l'}{l} \right)=2\] \[x\] \[\frac{l'}{l}\,={{10}^{2}}\,=l'=100l\]
You need to login to perform this action.
You will be redirected in
3 sec
