A small spotlight of radiant intensity illuminates a museum painting hung so that its…
PHYSICS · Subjective · Fermi University Physics · Optics & Photonics · Geometrical optics and imaging · Geometrical optics and imaging
Optics and Photonics, Ch Radiometry and photometry
Problem
A small spotlight of radiant intensity IΩ=80Wsr−1 illuminates a museum painting hung so that its flat surface is tilted: the normal to the painting makes an angle of 40∘ with the line joining the spotlight to the painting. The centre of the painting is 1.5m from the spotlight, which counts as a small source at this distance. Find the irradiance on the painting at that point.