An underwater swimmer sends a sound signal to the surface. If it produces 5 bears per second when compared with the fundamental tone of a pipe of 20 cm length closed at one end, what is the wavelength of sound in water? `("Take" v_("water")=1500 m//s and v_("air")= 360 m//s)`

Explanation

If f is the frequency of sound (which is independent of medium), according to given problem `f=f_(c)+-5`
But as `f_(c)=(v)/(4L)=(360)/(4xx0.2)=450Hz`
So`f=(450+-5)Hz :. lambda_(w)=(v_(w))/(f_(w))=(1500)/(450+-5)`
i.e, `lambda_(w)=3.30 m or 3.37 m`