Two glass plates are in contact at one end and are separated by a spacer of thickness .011mm at the other end. The gap between the plates is filled with water. The entire top plate is illuminated normally by a sodium light of wavelength 589nm in air. The indices of refraction of the glass plates and water are 1.55 and 1.33, respaectively. Bright parallel fringes (bands) are observed cross the top glass plate.
A) Draw a diagram for this problem including two reflected interfering light beams. Be sure to label all relevant quantities.
B) Write an expression for the phase difference between the two reflected interfering beams. use the symbol "t" to represent the thickness of the gap.
C) Does the region along the edge of contact between the two plates appear to be bright or dark? Must justify your answer.
D) Find the number of bright parallel fringes crossing the entire length of the top glass plate.