The radius of the $2^{nd}$ orbit of $B^{4+}$ ion is:

Which of the following statements are correct?
$I$) The energy of hydrogen atom in its ground state is $-13.6 \ eV$
$II$) On the basis of Bohr's model,the radius of the $3^{rd}$ orbit of hydrogen atom is $158.7 \ pm$
$III$) The order of radius of the first orbit of $H, He^{+}, Li^{2+}$ and $Be^{3+}$ is $H > He^{+} > Li^{2+} > Be^{3+}$

The separation energy of the electron present in the shell $n = 3$ is $1.51 \ eV$. What is the energy in the first excited state? ............ $eV$

Consider one $He^{+}$ ion is in excited state $(n = 5)$. Which of the following observations hold true as per the Bohr's model?

In Bohr's atomic model,the radius $(r)$ and energy $(E)$ of an orbit $(n)$ are related as:

$A$ $150 \ W$ bulb emits light of wavelength $6600 \ \mathring{A}$ and only $8 \%$ of the energy is emitted as light. How many light photons are emitted by the bulb per second?