Initial frequency \(=205 \,Hz\)
String tightned so frequency is increased \(=205+f\)
Final frequency of string \(-\) frequency of tuning fork \(=3\) beats
\(205+f-205=3\)
\(\therefore f=3\)
\(\therefore\) Final frequency \(=205+3=208 \,Hz\)
$[\,dB$ માં લબ્ધિ $\left.=10 \log _{10}\left(\frac{ P _{ o }}{ P _{i}}\right)\right]$