$\Rightarrow n \propto \frac{{\sqrt T }}{{lr}}$
==> $\frac{{{n_1}}}{{{n_2}}} = \sqrt {\frac{{{T_1}}}{{{T_2}}}} \times \frac{{{l_2}}}{{{l_1}}} \times \frac{{{r_2}}}{{{r_1}}}$
$ = \sqrt {\frac{T}{{3T}}} \times \frac{{3l}}{l} \times \frac{{2r}}{r} = 3\sqrt 3 $
==> ${n_2} = \frac{n}{{3\sqrt 3 }}$
$y = \frac{{10}}{\pi }\,\sin \,\left( {\frac{{2\pi }}{T}t - \frac{{2\pi }}{\lambda }x} \right)$
For what value of the wavelength the wave velocity is twice the maximum particle velocity ..... $cm$ ?