Explanation

(c) The transverse vibrations of a string are determined by Melde’s method.
The frequency of vibration of a string of length l, mass per unit length m and vibration in p loops under tension T is given by
$n = \frac{p}{2l}\sqrt{\frac{T}{m}}$
Or
$p\sqrt{T} =$constant
If n, l and m are constant
Hence,
$T \propto \frac{1}{p^{2}}\ $
$\therefore\frac{T_{1}}{T_{2}} = \frac{p_{2}^{2}}{p_{1}^{2}}$
Or
$\frac{(50 + 15)}{T_{2}} = \frac{(6)^{2}}{(4)^{2}}$
Or
$\frac{65}{T_{2}} = \frac{36}{16}$
$\therefore T_{2} = \frac{65 \times 16}{36} = 26g$
So, weight removed from the pan
=65-29
=36 g
=0.036 kg-wt