In the case of a scattering surface, a single incident ray
can generate tens, hundreds or even thousands of rays.
If the incident ray
is in the region defined by [[phi].sub.i] [less than or equal to] (n[pi])/2, the [[phi].sub.i] and [[phi].sub.d] angles are maintained equal to Luebbers (see Figure 2(a)), but if the incident ray
arrives in the region [[phi].sub.i] [greater than or equal to] (n[pi])/2, the face assignments are exchanged, see Figure 2(b), and Luebbers' conditions are applied defining
In our case, element axis from input ends referred to as the optical axis is the angle between the line and the line along the incident ray
[L.sub.i1], while the element axis from the output ends referred to as the optical axis is the angle between the line [O'.sub.1][P.sub.4] and the line along the incident ray
Then, on invoking the Fermat's principle in Equation (4), the direction of the reflected rays could be determined from the incident ray
in Figure 2(b).
One incident ray
in the illuminating beam is shown (red line); it meets the stone at a point where the normal to the surface is oriented 0 degrees to the right of the vertical axis.
At point 1 and 2, rays are refracting and they appear from the incident ray
, one reflected and another one refracted where both are with certain power carrier .
An incident ray
travels between these small particles in the soil.
The lens plane is located at z = 2c and rays of light w[m.sub.0] and [m.sub.0][p.sub.0] are the principal incident ray
and reflected ray, respectively.
where [[rho].sup.i.sub.e] is the radius of curvature of the incident wavefront at [Q.sub.d] taken in the plane containing the incident ray
and the unit vector tangent to the edge at [Q.sub.d]; [[rho].sub.g] is the radius of curvature of the edge at [Q.sub.d]; [??] is the unit normal to the edge directed away from the center of curvature; [[beta]'.sub.0] is the angle between the incident ray
and the tangent to the edge at [Q.sub.d]; and [??]' and [??] are, respectively, unit vectors in the direction of incidence and diffraction.
When an incident ray
arrives at the surface of the silicon wafer, it is divided into the refraction ray which is absorbed by the silicon and the reflection ray which is reflected back to the air.
However, SBR requires a huge calculation time for electrically large targets because the results converge only if the density of the incident ray
tubes is greater than ten rays per wavelength  and because its calculation time is proportional to the number of incident ray
* MODERNISED: Percy Shaw from The road studs use a built in solar powered LED that is automatically illuminated from dusk till dawn and is visible from up to 10 times further than a traditional cat's eye that contain 'retroreflectors' - optical devices that reflect light rays back along a path parallel to that of the incident ray