Задача 40332.

On a pole, at heights of 3 m and 4 m above the surface of the earth, two lamps hang one above the other, each with a luminous intensity J of 200 cd. Find the illumination of the earth´s surface at a distance I = 2 m from the base of the pillar.

Detailed solution with a brief record of the conditions, formulas and laws used in the solution, derivation of the calculation formula and answer.
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