In hydrogen atom an electron revolves in a circular path. If the radius of its path is 0.53Ao and it makes 7×1015 revolution per second, its angular momentum about proton is
The mass of an electron is 9 x 10-31 kg. It revolves around the nucleus of an atom in a circular orbit of radius 4.5 Å, with a speed of 8 x 105 m/s. The angular momentum of electron is