Can u help me with answering these: 4. electromagnetic wavelengths immediately outside the violet end of the visible range
6. all of the frequencies or wavelengths of electromagnetic radiation

The two most prominent wavelengths in the light emitted by a hydrogen discharge lamp are 656(red) and 486 (blue). light from a hydrogen lamp illuminates a diffraction grating with 500 lines per mm, and the light is observed on a screen 1.50 behind the grating. what is the distance between the first-order red and blue fringes?