Answer
(a) $318.51Hz$
(b) $1.099m$
Work Step by Step
(a) We can determine the required frequency as follows:
$\nu=\sqrt{\frac{F}{Lm}}$
We plug in the known values to obtain:
$\nu=\sqrt{\frac{7m/s}{(0.3m)(0.23\times 10^{-3}Kg)}}$
$\nu=318.51Hz$
(b) The required wavelength can be calculated as follows:
$\lambda=\frac{v}{\nu}$
We plug in the known values to obtain:
$\lambda=\frac{350m/s}{318.51Hz}$
$\implies \lambda=1.099m$
