The energy associated with the first orbit of $He^{+}$ is

What is the maximum number of emission lines when the excited electron of an $H$ atom in $n=6$ drops to the ground state?

Assertion : For Balmer series of hydrogen spectrum,the value $n_1 = 2$ and $n_2 = 3, 4, 5...$
Reason : The value of $n$ for a line in Balmer series of hydrogen spectrum having the highest wavelength is $4$ and $6$.

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?

In the atomic spectrum of hydrogen,the series of lines observed in the visible region is:

Find the radius of the first,second,and third orbits of the hydrogen atom.