The de-Broglie’s wavelength of electron present in first Bohr orbit of Hydrogen atom is  

For first Bohr orbit of $"H"$ atom has
Radius  $\left(r\right)=0.529A^0$   $Mvr=\frac{h}{2\pi }$  $2\pi r=\frac{h}{mv}=\lambda$     $\lambda =2\pi \times 0.529A^0$