When passed through a diffraction grating with a slit spacing of $0\mathrm{.}004$ mm $(4106$ m$),$ the first$-$order fringe for light of a single wavelength lies a distance of $27\mathrm{.}8$ cm from the center of a screen located $1\mathrm{.}9$ m from the grating.

NOTE: This is a multi$-$part question. Once an answer is submitted, you will be unable to return to this part.$$

What is the wavelength of the light?

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The wavelength of the light is nm$.$