Textbook Problem

An investigator finds at a fiber at a crime scene that he wishes to use as evidence against a suspect. He gives the fiber to a technician to test the properties of the fiber. To measure the diameter of the fiber, the technician places it between two flat glass plates at their ends as in Figure P24.24. When the plates, of length 14.0 cm, are illuminated from above with light of wave-length 6.50 × 10² nm, she observes bright interference bands separated by 0.580 mm. What is the diameter of the fiber?