The wavelength associated with the electron moving in the first orbit of hydrogen atom with velocity $$2.2 \times 10^6 \mathrm{~ms}^{-1}$$ (in nm) is

$$\left(m_e=9.0 \times 10^{-31} \mathrm{~kg}, h=6.6 \times 10^{-34} \mathrm{Js}\right)$$

The energy required (in eV) to excite an electron of H -atom from the ground state to the third state is

The maximum number of electrons present in an orbital with $$n = 4, l = 3$$ is