These look like questions asked in conjunction with some lab experiment.
Singly-ionized helium, which has a hydrogenlike spectrum, would have more than two wavelength series, just as hydrogen does. The shortest wavelength series limit would be at 1/4 of the Lyman series wavelength of hydrogen, or at 22.7 nm . A wavelength of 30.4 nm would correspond to the Balmer series, but there are others at longer wavelengths.
http://www.daviddarling.info/encyclopedia/L/Lyman_series.html
The answer to your second question depends upon the diffraction grating that was used. I have no idea what experiment is being talked about. Are you writing a lab report for an experiment you did not witness?
the shortest and longest wavelength series in singly ionized helium is 22.8nm and 30.4nm . Are they right?
How many orders we can see between the angles range observations 30 and 90 in the Balmer's series?
1 answer
4 answers