If the ionisation energy for the hydrogen atom is 13.6 eV , then the energy required to excite it from the ground state to the next higher state is nearly

Using Bohr's model, the orbital period of electron in hydrogen atom in $\mathrm{n}^{\text {th }}$ orbit is ( $\mathrm{m}=$ mass of electron, $\mathrm{h}=$ Planck's constant, $\mathrm{e}=$ electronic charge, $\varepsilon_0=$ permittivity of free space)

The spectral series observed for hydrogen atom found in visible region is

In hydrogen atom, if $\mathrm{V}_{\mathrm{n}}$ and $\mathrm{V}_{\mathrm{p}}$ are orbital velocities in $\mathrm{n}^{\text {th }}$ and $\mathrm{p}^{\text {th }}$ orbit respectively, then the ratio $\mathrm{V}_{\mathrm{p}}: \mathrm{V}_{\mathrm{n}}$ is