47.22 Candelas
sâ = 500 mm; distance between the photometer to lamp 1.
sâ = 300 mm; the distance between the photometer to lamp 2.
Iâ = 17 cd; the intensity of lamp 2.
Using the formula;
Iâ = Iâ ¡ (sâ² á sâ²).
Iâ = 17 cd ¡ (250000 mm² á 90000 mm²).
Iâ = 47.22 cd;
Thus; Â the intensity of lamp 1 is 47.22 cd
Candela is the base unit of luminous intensity in the International System of Units (SI).