A laser beam with wavelength \(633 \mathrm{nm}\) is split into two beams by a
beam splitter. One beam goes to mirror 1 , a distance \(L\) from the beam
splitter, and returns to the beam splitter, while the other beam goes to
mirror \(2,\) a distance \(L+\Delta x\) from the beam splitter, and returns to the
beam splitter. The beams then recombine and travel to a detector together. If
\(L=1.00000 \mathrm{~m}\) and \(\Delta x=1.00 \mathrm{~mm},\) which best describes
the kind of interference observed at the detector? (Hint: To double-check your
answer, you may need to use a formula that was originally intended for
combining two beams in a different geometry.)
a) purely constructive
b) purely destructive
c) mostly constructive
d) mostly destructive
e) neither constructive nor destructive