In a double-slit experiment, we measure the following separation between 2 consecutive bright fringes: 3.3mm, 3.4mm, 3.4mm. The screen distance is D=2m. The slit width is a=0.04mm. The slit separation is d=0.25mm. What is the average wavelength of the laser and its alpha mss?
a. 628+-4nm
b. 520+-3nm
c. 421+-4nm
d. 325+-9nm