Figure P.9.31 illustrates a setup used for testing lenses. Show thatd = x2(R1 – R1,)/2R1R2...

Figure P.9.31 illustrates a setup used for testing lenses. Show that

d = x2(R1 – R1,)/2R1R2

when d1 and d2 are negligible in comparison with 2R1, and 2R2, respectively. (Recall the theorem from plane geometry that relates the products of the segments of intersecting chords.) Prove that the radius of the mth dark fringe is then

How does this relate to Eq. (9.43)?