In the Bohr model, the ratio of the kinetic energy (K) to the potential energy (U) of an electron in the nth orbit is:

The ratio of the wavelengths of the photons emitted when an electron in a hydrogen atom jumps from the 3rd orbit to the 2nd orbit and from the 4th orbit to the 3rd orbit is:

If the kinetic energy of an electron in an atom is $10.2$ eV and its potential energy is $-20.4$ eV, what is its total energy?

When the wave of hydrogen atom comes from infinity into the first orbit then the value of wave number is

An electron with kinetic energy $5\,\,eV$ is incident on a $H$-atom in its ground state. The collision

The extreme wavelengths of Paschen series are

Hydrogen atom emits blue light when it changes from $n = 4$ energy level to the $n = 2$ level. Which colour of light would the atom emit when it changes from the $n = 5$ level to the $n = 2$ level

According to Bohr’s theory, the moment of momentum of an electron revolving in second orbit of hydrogen atom will be

According to Bohr's model, an electron transitioning from the n=4 to n=2 state in a hydrogen-like ion emits a photon with a wavelength of 486 nm. What is the atomic number (Z) of this ion?

Given the Rydberg constant is $10^7 m^{-1}$, calculate the wavelength of the last line of the Balmer series in the hydrogen spectrum.

Energy required for the electron excitation in $L{i^{ + + }}$ from the first to the third Bohr orbit is