A sonometer wire supports a 4 kg load and vibrates in fundamental mode with a tuning fork of frequency 416 Hz. The length of the wire between the bridges is now doubled. In order to maintain fundamental mode, the load should be changed to
Here is the frequencyis the length of the is the mass is the force due to load (tension).
-----------1
----------2
In order to maintain the same fundamental mode
squaring both sides of the equation (1) and (2) and then equation
therefore, solving we get m2 =16 kg