A laser beam with wavelength 10.6 $\mu$m is split into two beams by a beam splitter in a Michelson interferometer.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 same beam splitter.The beams then recombine and go to a detector together.If L = 1.00000 m and $\Delta$x = 1.20000 mm,which best describes the kind of interference at the detector?

Question

Quizplus · Accepted Answer

In a Michelson interferometer, interference occurs when the two beams recombine at the detector. This interference can be constructive or destructive depending on the path length difference between the two beams. 
In this case, the path length difference is given by F1F1F1S1F1F1F10x = 1.20000 mm. Since this is equal to half of the wavelength of the laser beam (10.6 F1F1F1S1F1F1F10m/2 = 0.0053 mm), the interference will be mostly destructive. This is because the two beams are out of phase by half a wavelength, so when they recombine, they will interfere destructively and cancel each other out to some extent. Therefore, the correct answer is (D) mostly destructive.

A Laser Beam with Wavelength 10 μ\muμ M Is Split into Two Beams by a Beam Splitter

A Laser Beam with Wavelength 10 $\mu$ M Is Split into Two Beams by a Beam Splitter