An Optical Engineer Needs to Ensure That the Bright Fringes $15.7 \mathrm {~mm}$

Multiple Choice

An optical engineer needs to ensure that the bright fringes from a double-slit are $15.7 \mathrm {~mm}$ apart on a detector that is $1.70 \mathrm {~m}$ from the slits. If the slits are illuminated with coherent light of wavelength $633 \mathrm {~nm}$ , how far apart should the slits be?

A) $63.0 \mu \mathrm { m }$
B) $68.5 \mu \mathrm { m }$
C) $79.5 \mu \mathrm { m }$
D) $74.0 \mu \mathrm { m }$