A total of 35 bright and 35 dark Newton’s rings (not counting the dark spot at the center) are observed when 560-nm light falls normally on a planoconvex lens resting on a flat glass surface (Fig. 24–31). How much thicker is the lens at the center than the edges?
Figure 24-31 Newton’s rings. (a) Light rays reflected from upper and lower surfaces of the thin air gap can interfere.
Figure 24-31 Newton’s rings. (b) Photograph of interference patterns using white light.
Source: Giancoli, Douglas C., Physics: Principles with Applications, 7th Edition, 2014.
$9.8 \; \mu m$