12: Light Flashcards
Define convergent rays.
Light rays that meet at a point.
Define divergent rays.
Light rays that spread out from a point.
Define incident ray.
A light ray that hits a reflecting surface.
Define reflected ray.
A light ray that bounces off a reflecting surface.
Define normal.
A perpendicular line to the reflecting surface at the point of incidence.
Define point of incidence (O).
The point at which an incident ray hits a reflecting surface.
Where is the angle of incidence?
Between the incident ray and the normal.
Where is the angle of reflection?
Between the reflected ray and the normal.
What is the first law of reflection?
The incident ray, reflected ray, and the normal all lie in the same (2D) plane.
What is the second law of reflection?
The angle of incidence is equal to the angle of reflection.
What kind of reflection is caused by a smooth surface?
Regular reflection.
What kind of reflection is caused by a rough surface?
Diffuse (irregular) reflection.
Define lateral inversion.
Image is flipped horizontally.
Define inversion.
Image is flipped horizontally and vertically.
Define real.
Image is projected onto a surface.
Define virtual.
Image is reflected in a reflective surface.
Define magnified.
Image is bigger than object.
Define diminished.
Image is smaller than object.
What are the four applications of mirrors?
Vision testing
Blind corner mirrors
Instrument scale (weight)
Periscope
How are mirrors applied in vision testing?
Mirrors make letters and numbers appear further away than they are.
How are mirrors applied in instrument scales?
A mirror is placed behind the pointer to avoid parallax error.
How are mirrors applied in periscopes?
Two mirrors inclined at 45° make a periscope.
