Unit 2 Terminology PW2 Flashcards
Law of Reflection
an incident wave or particle will reflect at the same angle that it hit a barrier.
Regular Reflection
All rays in a beam of light are reflected at the same angle (smooth objects).
Diffuse Reflection
when the rays in a beam of light are scattered off a surface.
Reflex Reflection
when an incident ray is reflected back the way it came
Normal
a line that is perpendicular to the point of incidence.
Plane Mirror
Flat mirror
Point of incidence
The point where the light hits the mirror
Angle of Incidence
the angle between the normal and the incident ray.
Angle of Reflection
the angle between the normal and the reflected ray.
Virtual Images
an image light only appears to pass through.
Reflected ray
the incident angle after reflection
Curved Mirrors
Several tiny plane mirrors at slightly different angles.
Concave Mirrors
A curved mirror with a rough outside, converging mirror.
Convex Mirrors
A curved mirror with a rough inside, diverging mirror.
Vertex (v)
the geometrical center of a curved mirror.
Center of Curvature (C)
the geometrical center of the sphere the mirror is made from.
Principal Axis
a line that passes through the center of curvature and the vertex.
Radius of Curvature (R)
the distance from the center of curvature to the vertex.
Focal Point (F)
a point on the principal axis halfway between C and V. Real on a concave mirror but virtual on convex.
Focal Length (f)
distance between the focal point and the vertex.
The principal rays for mirrors
- A ray travelling parallel to the principal axis will reflect through the focal point.
- A ray travelling through the focal point will reflect parallel to the principal axis.
- A ray travelling through C will reflect back in the same direction.
Convex Mirror Characteristics
All images will be smaller, upright, virtual, and between the f and V.
Medium
the substance light is travelling through.
Refraction
when light travels from one medium to another it bends.
Index of Refraction (n)
a comparison of the speed of light in that substance with the speed of light in a vacuum.
Interface
The point at which two media meet.
Point of Incidence
The point in the interface where the light bends.
Refracted Ray
the ray that leaves the interface through the second medium.A
Angle of Refraction
the angle between the refracted ray and the normal.
Snells Law
n1<n2>n2 the light will bend away from the normal.</n2>
Critical Angle
the angle of incidence producing an angle of refraction of 90 degrees.
Total Internal Reflection
When the angle of incidence is greater than the critical angle, the ray reflects.
Lens
a transparent optical device with a clear lens.
Converging lens
thicker in the middle than at the ends.
Optical Center (O)
The center of the lense.
Principle Focus (F)
the point that rays travelling parallel to the principle axis appear to converge through. Converging lenses its always on the opposite side the light comes from.
Secondary Focus (F1)
the focal point on the opposite side of the lens as F. Same side as the light for a converging mirror.
Construction Line
The normal for a lens.
Real Images
in a lens, a real image will appear on the opposite side the light came from.
Virtual Images
appears on the same side the light originated from in a lens.
Diverging Lens
thinner in the middle than on the ends.
Principle ray for Diverging Lenses
- A ray travelling parallel to the principle axis will appear to refract from the principle focus.
Principle rays for Converging Lenses
- A ray travelling parallel to the principle axis will refract through the principle focus.
- A ray travelling through the secondary focus will refract parallel to the principle axis.
- A ray travelling through O will continue.
