For a hydrogen atom with $n = 1$,the radius of the Bohr orbit is approximately $0.530 \, \mathring{A}$. What will be the radius for the first excited state $(n = 2)$ in $\mathring{A}$?

The quantity $h \nu / K_{B}$ corresponds to

When an electron drops from a higher energy level to a lower energy level,then

For a $H$ atom,the energy transition from $n = 1$ to $n = 2$ is $10.2 \ eV$. What will be the energy for the same transition in $Be^{3+}$ ion?

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 following figure shows the spectrum of an ideal black body at four different temperatures. The number of correct statement$(s)$ from the following is $..............$.
$A$. $T_4 > T_3 > T_2 > T_1$
$B$. The black body consists of particles performing simple harmonic motion.
$C$. The peak of the spectrum shifts to shorter wavelength as temperature increases.
$D$. $\frac{T_1}{v_1} = \frac{T_2}{v_2} = \frac{T_3}{v_3} \neq \text{constant}$
$E$. The given spectrum could be explained using quantization of energy.