Hello candidate,

As per the Bohr's postulates, the angular momentum of an electron moving in an orbit is an integral multiple of h/2π. So, mvr= nh/2π, where we take n equal to 1.

As we know that the expression for radius is equal to 0.529×n^2/Z Angstrom, where we take both n and z equal to 1. So, the expression for velocity becomes v= {h/2π}/(0.529×10^-10 × m), which upon calculation becomes 1.6 * 10^-16, moving in the first orbit of hydrogen like species.

Hope it helps!!