The distance between the $4^{th}$ and $3^{rd}$ Bohr orbits of $He^{+}$ is $:-$

Which of the following corresponds to the energy of a possible excited state of hydrogen (in $eV$)?

Based on equation $E = - 2.178 \times 10^{-18} \ J \left( \frac{Z^2}{n^2} \right)$,certain conclusions are written. Which of them is not correct?

Given below are two statements.
Statement $I:$ According to Bohr's model of an atom,qualitatively the magnitude of velocity of electron increases with decrease in positive charges on the nucleus as there is no strong hold on the electron by the nucleus.
Statement $II:$ According to Bohr's model of an atom,qualitatively the magnitude of velocity of electron increases with decrease in principal quantum number.
In the light of the above statements,choose the most appropriate answer from the options given below:

$A$ bulb emits electromagnetic radiation of $660 \, nm$ wavelength. The total energy of radiation is $3 \times 10^{-18} \, J$. The number of emitted photons will be :
$(h = 6.6 \times 10^{-34} \, J \cdot s, \, c = 3 \times 10^{8} \, m/s)$

Based on the equation $E = -2.178 \times 10^{-18} \ J \left( \frac{Z^2}{n^2} \right)$,certain conclusions are written. Which of them is not correct?