Point emitter
= Point emitter
An ideal <point emitter> emits <radiant flux> from one location. It approximates a physical source when its emitting dimensions are small relative to the distances relevant to the calculation. With <isotropy>, its <radiant intensity> is $I=\Phi/(4\pi)$ for total <radiant flux> $\Phi$. An extended source generally requires integrating contributions from different emitting positions.