Answer
See the answer below.
Work Step by Step
a) The most energetic is the one with the shortest wavelength: 357.9 nm.
b) Since it's close to the lower boundary of the visible spectrum (400 nm), it's a purple color.
You can help us out by revising, improving and updating this answer.
Update this answerAfter you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.