Answer
$\lambda = 1.06\times 10^{-5}~m$
$f = 2.83\times 10^{13}~Hz$
Work Step by Step
We can find the wavelength as:
$\lambda = \frac{2L}{m}$
$\lambda = \frac{(2)(0.5300~m)}{100,000}$
$\lambda = 1.06\times 10^{-5}~m$
We can find the frequency as:
$f = \frac{v}{\lambda}$
$f = \frac{3.0\times 10^8~m/s}{1.06\times 10^{-5}~m}$
$f = 2.83\times 10^{13}~Hz$