In a hypothetical Bohr hydrogen atom, if the mass of the electron is doubled, then the energy of the electron in the first orbit is: (in $\text{ eV}$)

In Bohr's atomic model, the energy of the electron is $E$ in the second orbit of a hydrogen atom. The energy of the electron in the third orbit of a helium atom $(Z = 2)$ will be:

Monochromatic radiation of wavelength $\lambda$ is incident on a hydrogen sample containing atoms in the ground state. Hydrogen atoms absorb the light and subsequently emit radiations of ten different wavelengths. The value of $\lambda$ is.....$nm$.

The difference between the radii of $n^{\text{th}}$ and $(n+1)^{\text{th}}$ orbits of a hydrogen atom is equal to the radius of the $(n-1)^{\text{th}}$ orbit of hydrogen. The angular momentum of the electron in the $n^{\text{th}}$ orbit is $.........$ ($h$ is Planck's constant).

Which of the plots shown in the figure represents speed $(v)$ of the electron in a hydrogen atom as a function of the principal quantum number $(n)$?

To accommodate the view that matter is made up of $5$ elements only,a scientist proposed the following hypothesis: atoms can have a maximum principal quantum number $n_{\max}$ and no higher. Then,which of the following statements must be true?