The angular momentum of an electron in an $H$ atom in a particular $n$ state is $\frac{h}{\pi}$. What is the energy in $J$ required to excite the electron from this particular $n$ state to $(n+1)$ state? $(x = 2.18 \times 10^{-18} \ J)$

Assertion : The radius of the first orbit of hydrogen atom is $0.529 \ \mathring{A}$.
Reason : Radius of each circular orbit $(r_n) = 0.529 \ \mathring{A} \ (n^2/Z)$,where $n = 1, 2, 3$ and $Z =$ atomic number.

The ionization energy of $He^+$ is $19.6 \times 10^{-18} \ J \ atom^{-1}$. What is the energy of the first stationary state $(n = 1)$ of $Li^{2+}$?

Which one of the following about an electron occupying the $1s$ orbital in a hydrogen atom is incorrect? (The Bohr radius is represented by $a_0$)

The wavenumber associated with the maximum energy in the Balmer series will be......

The emission spectrum of hydrogen is found to satisfy the expression for the energy change $\Delta E$ (in joules) such that $\Delta E = 2.18 \times 10^{-18} \left( \frac{1}{n_1^2} - \frac{1}{n_2^2} \right) \, J$ where $n_1 = 1, 2, 3 \dots$ and $n_2 = 2, 3, 4 \dots$. The spectral lines correspond to the Paschen series when: