Waves travel in straight line perpendicular to the wave front.

The rectilinear property applies to both plane and circular waves.

Look at the picture below.

Both circular and plane waves can be reflected, obeying the law of reflection.Some of the reflectors are:

a)Straight reflectors

b)Concave reflectors

c)Convex reflectors

Reflection of straight waves.

Reflection of plane/straight waves by straight reflector at an oblique angle tothe path of waves

Reflection of straight on straight reflector at 90 degrees to the path of incident wave

 Reflection of straight waves on a concave reflector

Reflection of straight waves on a concave reflector

For the concave reflector:
a) The reflected waves take the shape of the reflector(are concave)
b) Converge to the point in front of the reflector; this means that this reflector
has a real focus (focal point).

Reflection of straight waves on a convex reflector.

The reflected waves are convex.
-The waves appear to diverge from a point behind the
reflector.
-This point is the focus of the reflector.

Reflection of circular waves

1.Reflection by straight reflector

The point of incidence serves as a source of reflected circular waves

The radius of the reflected rays increases from the source.

2.Reflection on a concave reflector

By concave reflector.
concave reflector produces straight reflected waves