For which one of the following,is the Bohr model not valid?

The momentum of an electron revolving in the $n^{\text{th}}$ orbit is given by: (Symbols have their usual meanings)

$A$ hydrogen atom changes its state from $n=3$ to $n=2$. Due to recoil,the percentage change in the wavelength of emitted light is approximately $1 \times 10^{-n}$. The value of $n$ is . . . . . . .[Given $Rhc=13.6 \text{ eV}, hc=1242 \text{ eV nm}, h=6.6 \times 10^{-34} \text{ J s}$,mass of the hydrogen atom $=1.67 \times 10^{-27} \text{ kg}$]

The radius of the orbit of an electron in a $H$-atom changes from $2.12 \mathring{A}$ to $4.77 \mathring{A}$. The $H$-atom has:

The ratio of areas within the electron orbits for the first excited state to the ground state for a hydrogen atom is (in $ : 1$)

If the electronic charge on an electron alone is doubled, then as per the Bohr model, the $K.E.$ of an $e^-$ revolving in the $n^{th}$ orbit becomes: