Final answer:
A ray diagram for illustrating the law of reflection includes a flat surface with a normal line and rays at equal angles of incidence and reflection.
Step-by-step explanation:
To draw a ray diagram that represents light reflecting off of a flat surface to illustrate the law of reflection, start by drawing a horizontal line to represent the flat surface. Next, draw a perpendicular line at the point where the light will strike the surface; this is known as the normal line or normal.
Now, draw an incoming light ray, the incident ray, hitting the surface at a point. The angle between this incident ray and the normal is called the angle of incidence. From the point where the incident ray meets the surface, reflect it off the surface, ensuring that the angle between the reflected ray and the normal, the angle of reflection, is equal to the angle of incidence. Remember, when drawing the ray diagram, according to the law of reflection, the angle of incidence is always equal to the angle of reflection.
By observing light reflecting from different surfaces, such as paper or a mirror, you can confirm the law of reflection by noticing that on smooth surfaces like mirrors, light reflects at specific angles, which creates what is known as specular reflection. This is in contrast to rough surfaces that cause light to reflect in many different directions, creating a diffuse reflection.