$3.$Two slits, each separated from its neighbor by d$=0\mathrm{.}06$ mm$,$ are illuminated by a coherent light source of wavelength $=550$nm$.$ The slits are extremely narrow. As screen is located L$=2\mathrm{.}5$m from the slits. The intensity on the centerline is $0\mathrm{.}05($W$/$m$2).$ Consider a location on the screen x$=1\mathrm{.}72$ cm from the centerline.a$)$Draw the phasors, according to the phasor model for the addition of harmonic waves, appropriate or this location.b$)$ From the phasor diagram, calculate the intensity of light at this location.