Question #38523

1 Answer
A08
May 24, 2017

#699nm#

Explanation:

As light travels to and from the mirror, for a distance of #lambda/2# to the mirror, one full wavelength #lambda# shift at the detector will be noted. We know that for #1# wavelength movement there is constructive interference. Hence, one fringe will move into a position previously occupied by the original fringe.

Fringes moved #=644#
Mirror moved #=0.225mm#
#"Number of fringes"xxlambda/2="Distance moved by movable mirror"#
#=>lambda=0.225xx2xx1/644=6.99xx10^-7m#

#=699nm#

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