According to Bohr's atom, velocity of electron is given by, ...(i) where, v = velocity of electron where, v = velocity of electron n = principal quantum number From Eq. (i), velocity of electron is directly proportional to atomicnumber of atom, corresponding to positive charge. So, as Z increases velocity also increases. Hence, statement I is false. Also, velocity of electron is inversely proportional to n i.e. as ‘n’ decreases velocity of electron increases. So, statement II is true.