According Bohr’s theory, correct statements are
A) Angular momentum of electron in 2^nd orbit of H-atom is $\frac{h}{\pi }$
B) Velocity of electron is proportional to  $\frac{Z}{n}$
C) Radius of first orbit of H-atom is 52.9 A⁰
D) Energy difference between 2^nd orbit and 1^st orbit of H-atom is greater than the energy difference between 3^rd orbit and 5^th orbit