I take we are taking about the visible spectra (Balmer Series)? The two spectra have similar number of lines as below, although some are very feint. That a line apears in the visible spectrum will depend on the separation of the energy levels. We do not see transitions to level 1 for hydrogen or helium because the energy is too high and these appear in the UV. At the other end of the visible spectrum the Paschen series appear in the infrared.
Helium
wavelengths (nm)
438.793
443.755
447.148
471.314
492.193
501.567
504.774
587.562
667.815
Hydrogen (nm) transition
383.5384 9 -> 2 Violet
388.9049 8 -> 2 Violet
397.0072 7 -> 2 Violet
410.174 6 -> 2 Violet
434.047 5 -> 2 Violet
486.133 4 -> 2 Bluegreen (cyan)
656.272 3 -> 2 Red
Why is the helium spectrum have so many more lines than the hydrogen spectrum?
1 answer