Reflection from Convex Mirror

TM 9-258

rays will be deflected in a divergent manner. The reason

2-8.

Reflection from Convex Mirror.

for this can be, determined by plotting the angles of

a. The law of reflection holds true for all surfaces

reflection of individual rays in relation to their angles of

whether convex, concave, or plane. The action of

incidence and the normals for each ray. In this case, the

various curved surfaces in directing the course of the

normal for each ray is an imaginary line drawn from the

reflected light will vary according to the amount of

center of curvature of the mirror to the point of incidence

curvature of the reflecting surface and the overall effect

of the ray. The angle of reflection will be equal to the

will be dependent on the distance of the light source from

angle of incidence for each ray.

the reflecting surface.

b. Assume that light from a practically infinitely

distant source, such as the sun (practically parallel rays),

strikes a convex mirror (fig 2-18). It will be found that the

Figure 2-18. Reflection from convex mirror, infinitely distant source.

c. If the light source is at a finite distance, or close to the mirror, the rays will be reflected in a divergent manner also.

Such rays will be reflected at different angles than would be the case if all of them struck the mirror as parallel rays.

2-9.

Reflection from Concave Mirror.

a. The law of reflection is again applied to locate the path of the reflected rays when plotting the reflection from a

concave mirror. In this instance, the center of curvature of the mirror is in front of the mirror (fig 2-19). Imaginary lines are

run from this center to the points of incidence of the incident rays, to indicate the normals of individual rays. When this has

been done, the reflected rays can be plotted so that each forms an angle of reflection which will be equal to the angle of

incidence of the corresponding ray.

2-13