Final answer:
Yes, lines in a diffraction grating can be too close together for visible light, but the grating can be suitable for other types of EM radiation with larger spacings between the lines.
Step-by-step explanation:
Yes, the lines in a diffraction grating can be too close together to be useful as a spectroscopic tool for visible light. When the lines in the grating are very close together, they can cause overlapping diffraction patterns, making it difficult to separate and interpret the individual wavelengths of light. However, diffraction gratings with smaller spacings can be suitable as a spectroscopic tool for other types of electromagnetic (EM) radiation, such as X-rays or ultraviolet (UV) light. These shorter wavelengths allow for larger spacings between the lines, resulting in distinct and measurable diffraction patterns.