The ratio of intensities between two coherent sound sources is $4: 1$. The difference of loudness in dB between maximum and minimum intensities when they interfere in the space is ..........
A$20 \log _{10}(3)$
B$10 \log _{10}(2)$
C$20 \log _{10}(2)$
D$10 \log _{10}(3)$
Medium
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C$20 \log _{10}(2)$
c (c)
Loudness in $dB =10 \log _{10} \frac{I}{I_0}$
Let $L_1=10 \log _{10} \frac{l}{I_0}$
$L_2=10 \log _{10} \frac{4 I}{I_0}$
$L_2-L_1=10 \log _{10} 4$
$=20 \log _{10} 2$
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