Question

1. An omni (general diffusive) point source with luminous intensity I = 100 cd to every direction is located at the center of an imaginary sphere of radius 1 meter. The illuminance (E) at any point on the sphere is ___________________ lx, while the point source provides a total of _________________ lm. Next, the point source is covered with a clear glass sphere of radius 10 meters (like a large light bulb). The clear glass has light transmittance of 0.6 (τ). The luminous intensity I’ on the inside surface of the glass sphere is _________________ cd, while the lumen output through the glass sphere to outside is ______________________ lm.

Answer 1