Laachtmäächt

Wan det laacht iin uun en rümwinkel ${\displaystyle \textstyle \Omega }$ strualet, do as det laachtmäächt ${\displaystyle \textstyle I_{\mathrm {v} }}$ di bröök faan laachtstruum ${\displaystyle \textstyle \Phi _{\mathrm {v} }}$ (uun Lumen, lm) an rümwinkel ${\displaystyle \textstyle \Omega }$ (uun Steradiant, sr).

${\displaystyle I_{\mathrm {v} }\,=\,{\frac {\Phi _{\mathrm {v} }}{\Omega }}}$

Amkiard as di laachtstruum ${\displaystyle \Phi _{\mathrm {v} \Omega }}$ det produkt faan laachtmäächt ${\displaystyle \textstyle I_{\mathrm {v} }}$ an rümwinkel ${\displaystyle \textstyle \Omega }$.

${\displaystyle \Phi _{\mathrm {v} \Omega }\,=\,I_{\mathrm {v} }\cdot \Omega }$