In an experiment such as that described in Problem 40.1, brightness is observed for the following film thicknesses: 2.90 × 10^-7 m, 5.80 × 10^-7 m, and 8.70 × 10^-7 m. 

(a) What is the wavelength of the light being used? 

(b) At what thicknesses would darkness be observed?

Problem 40.1

Figure 40-2 shows a thin film of a transparent material of thickness d and index n_f where n₂ > n_f > n₁. For what three smallest film thicknesses will reflected light rays-1 and -2 interfere totally Constructively and Destructively?  Assume the monochromatic light has a wavelength in the film of 600 nm.

Transcribed Image Text:

nj n₂ 12 d Fig. 40-2