Although we have discussed single$-$slit diffraction only for a slit, a similar result holds when light bends around a straight, thin object, such as a strand of hair. In that case, aa is the width of the strand. From actual laboratory measurements on a human hair, it was found that when a beam of light of wavelength $633\mathrm{.}6$ nmnm was shone on a single strand of hair, and the diffracted light was viewed on a screen $1\mathrm{.}35$ mm away, the first dark fringes on either side of the central bright spot were $5\mathrm{.}34$ cmcm apart.