Calculate the wavenumber of a photon emitted during the transition from the orbit of $n=3$ to $n=2$ in a hydrogen atom. $(R_{H} = 109677 \ cm^{-1})$ (in $cm^{-1}$)

The radius (in $\mathring{A}$) of the $3^{rd}$ Bohr orbit in $Li^{2+}$ ion is closest to $......$ [Given: Atomic number of $Li = 3$]

Light,a well-known form of energy,is treated as a form of matter,by saying that it consists of:

The work function of a metal is $4.2 \, eV$. If radiation of $2000 \, \mathring{A}$ falls on the metal,then the kinetic energy of the fastest photoelectron is:

Consider the following spectral lines for atomic hydrogen:
$A$. First line of Paschen series
$B$. Second line of Balmer series
$C$. Third line of Paschen series
$D$. Fourth line of Bracket series
The correct arrangement of the above lines in ascending order of energy is:

The value of Planck's constant is $6.63 \times 10^{-34} \, J \cdot s$ and the speed of light is $3.0 \times 10^8 \, m \cdot s^{-1}$. The wavelength of a quantum of light with a frequency of $8 \times 10^{15} \, s^{-1}$ is closest to which of the following values in meters?