According to the quantum theory of light, energy of light is carried in discrete units called photons.
Number of spectral lines in hydrogen atom $\infty .$
Visible region of hydrogen spectrum was first studied by Balmer, therefore they are also called as Balmer lines.
Cathode$-$ray tubes that are used to convert electric signals into visible images may be divided into, for example, the following categories: television picture tubes, or kinescopes; cathode$-$ray oscillograph tubes; numerical indicator tubes; the indicator tubes used in radar sets
Neon street sign gives a line emission spectrum.
When neon atoms gain enough energy to become excited, light is produced. Atom releases a photon when it returns to a lower energy state.
Therefore, the source associated with a line emission spectrum is the neon street sign.
Fast moving electrons are associated with wave and hence they show diffraction.
Bohr's hypothesis
Electrons revolves round the nucleus in water orbits.
Orbit of the electron around the nucleus can take only some special values of radius.
The energy of the atom as a definite value in these orbits.
In this Orbits, Angular momentum $(e)$ of the electron is integral multiple of the plank's constant h divided by $2n$
$\text{i.e. l}=\text{n}\frac{\text{h}}{2\text{n}}.$
Ionization energy is given as:
$E = 13.6 Z2 eV$
For $Li^+, Z = 3$
$E = 13.6 \times 9$
$E = 122.4 eV$
A string is used to represent the behavior of a particle analogously to the waves traveling on it.
Particle waves can lead to standing waves held under resonant conditions.
When a stationary string is plucked, it causes several wavelengths to be excited. But, we know that only the ones which have nodes at the ends will survive.
$1 : 4 : 9$, In Bohr’s atomic model, $r_n n^2$
Hotter filament will increase the temperature.
Hence rate of electron emission will increase.
In a hydrogen atom, electron revolving around a fixed proton nucleus have some centripetal acceleration. Therefore its frame of reference is non$-$inertial. If the frame of reference, where the electron is at rest, the given expression is not true as it forms the non$-$inertial frame of reference.
When the electron beam strikes the screen coated with fluorescent material the electrical signals appear as visual pattern or spots on the screen.
The orbital quantum number, $l,$ divides the shells up into smaller groups of subshells called orbitals. The orbital quantum number describes shape of subshells. The principal quantum number$(n)$ determines the possible values of l. For $n = 1$ i.e.$ K-$shell there is no subshell so, $l = 0$ i.e. $(n − 1)$. Hence, The possible values of orbital quantum numbers are from $0$ to $(n − 1).$
In transition from $n_1 = 3$ and $n_2 = 4, 5, 6,….$
Infrared radiation of Paschen spectral is emitted.
The heated filament transfers its heat to the cathode the cathode coated by oxides of Barium or Strantium emit electrons on heating.
Phosphorus has atomic no$-17.$ so its $k$ shell has $2$ electron, $L$ shell has $8$ electron and $M$ shell has $5$ electron.