If the electron in a hydrogen atom jumps from an orbit with level $n_1=2$ to an orbit with level $n_2=1$,the emitted radiation has a wavelength given by

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 ionization potential of a hydrogen atom is $13.6 \ eV$. Hydrogen atoms in the ground state are excited by monochromatic radiation of photon energy $12.1 \ eV$. According to Bohr's theory,the number of spectral lines emitted by the hydrogen atoms will be:

The radii of the first four Bohr orbits of the hydrogen atom are related as:

The de-Broglie wavelength of an electron in the ground state of the hydrogen atom is

Match the following List-$I$ with List-$II$ in connection with Bohr's atomic model.

$A$. Speed of revolution of electron	$i$. $\frac{1}{4 \pi \varepsilon_0} \frac{2 \pi Z e^2}{n h}$
$B$. Kinetic energy	$ii$. $-\left(\frac{1}{4 \pi \varepsilon_0}\right)^2 \frac{2 \pi^2 m e^4 Z^2}{n^2 h^2}$
$C$. Total energy	$iii$. $\left(\frac{1}{4 \pi \varepsilon_0}\right)^2 \frac{2 \pi^2 m e^4 Z^2}{n^2 h^2}$
$D$. Frequency	$iv$. $\left(\frac{1}{4 \pi \varepsilon_0}\right)^2 \frac{4 \pi^2 Z^2 e^4 m}{n^3 h^3}$