The wavenumber associated with the maximum energy in the Balmer series will be......

If the velocity of the revolving electron of $He^{+}$ in the first orbit $(n=1)$ is $v$,what is the velocity of the electron in the second orbit $(n=2)$?

If in Bohr's model,for a unielectronic atom,the time period of revolution is represented as $T_{n,Z}$ where $n$ represents the shell number and $Z$ represents the atomic number,then the value of $T_{1,2} : T_{2,1}$ will be

The energy required for the ionization of an excited hydrogen atom would be (in $eV$)-

The ratio of the radius of the first orbit in hydrogen to the radius of the first orbit in deuterium is .......

When an electron jumps from $n = 5$ to $n = 2$ with all possible transitions,which of the following statements is correct?