$9\mathrm{.}7*$ Two parallel narrow slits in an opaque screen are separated by $0\mathrm{.}100$ mm$.$ They are illuminated by plane waves of wavelength $589$ nm$.$ A cosine$-$squared fringe pattern wherein consecutive maxima are $3\mathrm{.}00$ mm apart appears o$9\mathrm{.}7*$ Two parallel narrow slits in an opaque screen are separated by $0\mathrm{.}100$ mm$.$ They are illuminated by plane waves of wavelength $589$ nm$.$ A cosine$-$squared fringe pattern wherein consecutive maxima are $3\mathrm{.}00$ mm apart appears on a viewing screen. How far from the aperture screen is the viewing screen?n a viewing screen. How far from the aperture screen is the viewing screen?