Some of the wavelengths observed in the emission spectrum of neutral hydrogen gas are $912, 1026, 1216, 3646, 6563 \, \mathring{A}$. If broadband light is passing through neutral hydrogen gas at room temperature,then the wavelength that will not be absorbed strongly is .................. $\mathring{A}$.

$A$ sample of hydrogen atoms is in an excited state (all the atoms). The photons emitted from this sample are made to pass through a filter through which light having a wavelength greater than $800 \ nm$ can only pass. Only one type of photon is found to pass through the filter. The sample's initial excited state is: [Take $hc = 1240 \ eV \cdot nm$,ground state energy of hydrogen atom = $-13.6 \ eV$.]

The electron in a hydrogen atom makes a transition from an excited state to the ground state. Which of the following statements is true?

The number of spectral lines emitted by atomic hydrogen that is in the $4^{\text{th}}$ energy level is

When a hydrogen atom emits a photon during a transition from $n=4$ to $n=2$,its recoil speed is about (in $m \ s^{-1}$)

If $n$ is the orbit number of the electron in a hydrogen atom,the correct statement among the following is