An electron of mass ' m_e ' and charge ' e ' revolving around the nucleus in n^ th orbit has orbital magnetic moment enh 4 m_e which is equal to Bohr Magneton, the orbit number in which electron should revolve is ( h = Planck's constant)

Step-by-step solution

The orbital magnetic moment of an electron revolving in the n^ th orbit is given by M = n e h 4 m_e . The Bohr Magneton is defined as the orbital magnetic moment of an electron in the first orbit ( n=1 ), which is _B = e h 4 m_e . Given that the orbital magnetic moment is equal to the Bohr Magneton: n e h 4 m_e = e h 4 m_e n = 1 Thus, the electron should revolve in the first orbit. Answer: one