Given value,
Weight of a golf ball $= 200 \,g$
Movingwith speed $=5m/h=\frac{5}{60\times60}=\frac{5}{3600}m/sec$
From de-Broglie equation; $\lambda=\frac{h}{mv}$
Here, $h$ is proportionality constant of plank constant $=6.626 \times 10^{-34}\,kg\,m^{2}s^{-1}$
Wavelength, $\lambda=\frac{6.626\times10^{-34}}{200\times10^{-3}\times\frac{5}{3600}m/sec}$
$=\frac{6.62\times3600\times10^{-34}}{1000\times10^{-3}}$
Order of wavelength $= 10^{-30}\,m$