5. In the Cartesian coordinate system $x O y$, if the line $l$ bisects the circle $x^{2}+y^{2}-2 x-4 y=0$ and does not pass through the fourth quadrant, then the range of the slope of $l$ is
$l$ passes through the point $(1,2)$, combining with the graph we know $0 \leqslant k_{l} \leqslant 2$, so the range of the slope of $l$ is $[0,2]$.