For a given lens in a telescope, what are the two letters corresponding to the light that gives the worst and best resolutions, respectively? (E.g., if you think that C gives the worst and A the best resolution, answer CA.)
A. Green
B. Red
C. Yellow
D. Violet
E. Blue
F. Orange
Well, the highest frequency or shortest wavelength would give the best resolution. The highest frequency is violet.
At the long wavelength, low frequency end of the visible spectrum you have red.