Identify the incorrect statement from the following.

Let us analyze each statement:

Statement A: "A circular path around the nucleus in which an electron moves is proposed as Bohr's orbit."

This is correct. In Bohr's model, electrons move in fixed circular orbits around the nucleus.

Statement B: "An orbital is the one electron wave function."

This is correct. In quantum mechanics, an atomic orbital is described by the wave function \(\psi\), which is a one-electron wave function.

Statement C: "The existence of Bohr's orbits is supported by hydrogen spectrum."

This is correct. Bohr's model successfully explained the hydrogen emission spectrum and the energy levels matched the observed spectral lines.

Statement D: "Atomic orbital is characterised by the quantum numbers n and l only."

This is incorrect. An atomic orbital is characterised by three quantum numbers: the principal quantum number \(n\), the azimuthal quantum number \(l\), and the magnetic quantum number \(m_l\). The magnetic quantum number \(m_l\) determines the orientation of the orbital in space, and different values of \(m_l\) correspond to different orbitals (e.g., \(p_x, p_y, p_z\)).

Therefore, the correct answer is Option D.