He wants to illuminate superficially in a fair area of 50x100 square meters. According to Lambert's law, how many CD/m^2 luminosities should the ceiling of 50x100 m emitting light have so that the average illuminance level at P1, P2, and P3 points is 500 lux? The distance between the working plane (where the P points are) and the luminaire is 6.5 meters. The P points are at the midpoint of the 50-meter section.
P1
40m
P2
40m
P3
10m
A
A
10m
25m
A
25m
A