A room, with dimensions of $6$ m $($width$)\backslash$times $8$ m $($depth$)\backslash$times $3$ m $($height$),$ has a diffuse window on onewall, as shown in Figure Q$2$a$.($a$)$ If the outside surface of the window has an illuminance of $10000$ lx$,$ and the window has atransmittance of $0\mathrm{.}5.$ The center of the window is $2$ m above the floor. If the window isconsidered as a point source, what is the illuminance at the center of the space on the floor?