The red line in the Helium spectrum is longer than the red line in the hydrogen
spectrum. What does that tell us about the distance between n2 and n3 in helium as
compared with the distance between n2 and n3 in hydrogen?
What do you mean by the red line being longer. Do you mean the color is still red; however, the wavelength in He is longer (greater) than the wavelength in hydrogen. The Rydberg formula is
1/wavelength = R(delta n energy)
If wavelength (w) is greater for He, it means the fraction, 1/w, is smaller, so delta n energy must be smaller. Check out my thinking.