An electron with kinetic energy $E$ collides with a hydrogen atom in the ground state. The collision will be elastic

What is an emission line?

Inner shell electrons in atoms moving from one energy level to another lower energy level produce

$\frac{x}{x+4}$ is the ratio of energies of photons produced due to the transition of an electron of a hydrogen atom from its $(i)$ third permitted energy level to the second level and $(ii)$ the highest permitted energy level to the second permitted level. The value of $x$ will be.

Let $T_{1}$ and $T_{2}$ be the energy of an electron in the first and second excited states of a hydrogen atom,respectively. According to the Bohr's model of an atom,the ratio $T_{1}: T_{2}$ is

The figure indicates the energy level diagram of an atom and the origin of six spectral lines in emission (e.g.,line no. $5$ arises from the transition from level $B$ to $A$). Which of the following spectral lines will also occur in the absorption spectrum?