The equation of transverse wave in stretched string is $y=5\sin 2\pi \left[\frac{t}{0.04}-\frac{x}{50}\right]$  where distances are in cm and time in second. The wavelength of wave is

Given

$y=5\sin 2\text{π}\left(\frac{t}{0.04}-\frac{x}{50}\right)\mathrm{...}\left(1\right)$

Wave equation $y=\text{A}\sin \left(\omega t-kx\right)\mathrm{....}\left(2\right)$

Compare (1) & (2)

$\omega =\frac{2\text{π}}{0.04}$   $k=\frac{2\text{π}}{50}$

We know $k=\frac{2\text{π}}{\lambda }$

$\frac{2\text{π}}{\lambda }=\frac{2\text{π}}{50}$

$\therefore \lambda =50cm$