Let the source propagate a sound waves whose intensity at a point (initially) be l. suppose we consider a case when the amplitude of the sound wave is doubled and the frequency is reduced to one-fourth. Calculate now the new intensity of sound at the same point ?

Explanation

Given `a=2a_(0)`
`f=(f_(0))/(4)`
Formula : `1 prop a^(2)f^(2)`
To find `I_("new")= ??`
`I_("new") prop a^(2)f^(2)`
`I_("old") prop a_(0)^(2)f_(0)^(2)`
`I_("new") prop (2a_(0))^(2)((f_(0))/(4))^(2)`
`:. I_("new") prop (4)/(16) a_(0)^(2)f_(0)^(2)`
`rArr I_("new")=(I_("old"))/(4)`