Steradian
= Steradian
{title2=$\mathrm{sr}$}
{wiki}
A <steradian> is the <solid angle> subtended by a patch of <area> $r^2$ on a <sphere> of <radius> $r$. The whole <sphere> subtends $4\pi\,\mathrm{sr}$.
= Steradian
{title2=$\mathrm{sr}$}
{wiki}
A <steradian> is the <solid angle> subtended by a patch of <area> $r^2$ on a <sphere> of <radius> $r$. The whole <sphere> subtends $4\pi\,\mathrm{sr}$.