diff --git a/docs/sph3u7.md b/docs/sph3u7.md index 4c78e78..1f93918 100644 --- a/docs/sph3u7.md +++ b/docs/sph3u7.md @@ -791,6 +791,8 @@ A light wave that is **coherent** is **monochromatic** (of the same wavelength) By using mafs involving rays along a nodal line, the separation, $s$ between **nodal/anti-nodal** lines on the distant surface can be related to the distance from the slits to the screen, $D$, the separation between the slits, $d$, and the wavelength $\lambda$. $$s=\frac{\lambda D}{d}$$ +The number of nodal lines depends on the ratio $\frac{d}{\lambda}$. + **Dark fringe** positions on the screen are equally spaced at the same separation $s$ between the bright fringes. The perpendicular bisector with a length of $D$ is a **bright fringe**. (Source: Kognity)