Which energy level of the singly ionized carbon atom has the same energy as the ground state energy of the hydrogen atom?

The energy required to remove an electron from the first excited state of $Li^{++}$ is ......... $eV$.

The minimum energy required by a hydrogen atom in the ground state to emit radiation in the Balmer series is nearly: (in $eV$)

The following diagram indicates the energy levels of a certain atom. When the system moves from the $2E$ level to the $E$ level,a photon of wavelength $\lambda$ is emitted. The wavelength of the photon produced during its transition from the $\frac{4E}{3}$ level to the $E$ level is

$A$ hydrogen atom in its ground state is irradiated by light of wavelength $970 \mathring A$. Taking $hc/e = 1.237 \times 10^{-6} \text{ eV m}$ and the ground state energy of the hydrogen atom as $-13.6 \text{ eV}$,the number of lines present in the emission spectrum is

The energy of an electron in the $n^{th}$ orbit of a hydrogen atom is given by $E_n = - \frac{13.6}{n^2} \ eV$. How much energy in $eV$ is required to move an electron from the first orbit to the third orbit?