SCIENCE 10 QTR 2 (Lesson 2)

Reflection & mirrors

How light is reflected

Light rays travel in straight lines from a source. When a light ray hits an object, it can be reflected— this is how we see objects.

Materials that reflect light well

Objects that have shiny and smooth surfaces

Materials that do not reflect light well

Objects that have rough and dull surfaces

Law of Reflection

The angle of reflection (θr) is the same as the angle of incidence (θi). θr = θi

Regular/specular reflections

• Light strikes a smooth surface.

• Incident light rays strike the surface in a parallel orientation and are reflected in the same orientation.

Diffused reflections

• Light strikes a rough surface.

• Light is reflected in many directions while still following the law of reflection

Plane mirrors

• Flat reflective surfaces that create images of objects by reflecting light according to the law of reflection.

• Produce laterally inverted images.

• The image appearing at the back of the mirror is a virtual image.

Curved mirrors

• Either convex (outward) or concave (inward)

Parallel rays

A ray that travels parallel to the optic axis and is reflected through the focal point.

Chief ray/radical ray

A ray that travels through the center of the sphere and is reflected back along. the path it came.

Focal ray

A ray that travels through the focal point and is mirrored parallel to the optic axis.