What's the difference when I observe the emission lines of say, Hydrogen or Neon, on two diffraction gratings having different line spacings? Will there be colors that will only be observed in one and not the other? Thank you!
The different spacings will spread out the colors differently. Generally, the closer the spacing, the more spread out the colors will be. So, if before you couldn't resolve a doublet which is very close to each other (e.g. the sodium doublet), you may able to resolve it using a diffraction grating with closer spacing.
Thank you! I actually did the experiment and I thought I saw more colors when I changed to a grating having more lines per mm. I also thought that the spacings had become too little for some wavelengths of visible light to pass through, but I was wrong.