Gr.10 Physics - Reflection: Concave Mirrors

4 principal rays of concave mirrors

1. Incoming parallel to optical axis, reflects through focal point

2. Incoming through focal point, reflects parallel to optical axis

3. Incoming through center point, reflects straight back

4. Reflects at vertex with equal angles above and below axis

Types of curved mirrors

1. Concave(converging)

   1. Curves inward

2. Convex(diverging)

   1. Curves outward

Centre of curvature(C)

Centre of the sphere, whose surface forms the curved mirror.

Principal Axis(PA)

The line going through the center of curvature/center of the mirror.

It intersects the mirror at 90 degrees and is normal to the surface.

Vertex(V)

Point where the principal axis intersects the mirror.

Focal Point(F)

Aka: focus

The place where parallel lights rays that reflect off a smooth curve all pass through.

The focal point is halfway between the vertex and center of curvature.

It’s on the same side as the object.

Locate image in concave mirror

1. Draw Ray 1 from a point on object parallel to principal axis

2. Ray 1 reflects through F

3. Ray 2 is drawn from tip of object to V and reflects at the same angle as its incident ray angle.

4. Image is located where the 2 rays intersect.