Mirrors Flashcards
Reflection Definition
The change in direction of a light ray when it bounces off a surface.
How does light travel as long as it is moving through the same medium?
In a straight line.
Medium Definition
The substance through which light travels.
Ray Definition
A straight line with an arrowhead that shows the direction in which light waves are travelling.
What does Fermat’s Principle predict?
The path that light will take after reflecting from a surface or passing through more than one medium.
According to Fermat’s Principle. light follows the path that will take what?
The least time.
When light reflects from a surface and remains in one medium, its speed is what?
Constant
The path that takes the least time is the what path?
The shortest path.
Fermat’s Principle leads to what?
The Laws of Reflection
What is a ray of light coming toward a surface called?
Incident Ray
Incident Ray Definition
A ray of light that travels from a light source toward a surface.
What is the angle measured between the incident ray and a perpendicular line drawn from the point of contact of the incident ray at the surface called?
The angle of incidence
Angle of Incidence Definition
The angle between the incident ray and the normal in a ray diagram.
What is that perpendicular line called?
The Normal
Normal Definition
A line that is perpendicular to a surface where a ray of light meets the surface.
What begins at the point of contact?
The reflected ray
Reflected Ray Definition
A ray that begins at the point where the incident ray and the normal meet.
What is measured between the reflected ray and the normal?
The Angle of Reflection
Angle of Reflection Definition
The angle between the reflected ray and the normal in a ray diagram.
What lie on the same flat surface, or plane?
The incident ray, the normal, and the reflected ray
When you know the angle of incidence, you can predict what because they are the same?
The Angle of Reflection
The reflected ray always lies on the plane that is defined by what?
The Incident Ray and the Normal.
What are these relationships called?
The Laws of Reflection
The Laws of Reflection applies to what?
Light waves and to all other forms of waves, such as sound waves.
What do the Laws of Reflection state?
- The incident ray, the reflected ray, and the normal always lie on the same plane.
- The angle of reflection is equal to the angle of incidence.
What is the object placed in front of a mirror called?
An object.
What is the likeness that is seen in the mirror called?
The image of the object.
If you apply the laws of reflection to rays going from the object, you can predict what?
Where the image will be and what the image will look like; the characteristics of the image.
Plane Mirror Definition
A mirror with a flat, reflective surface.
What is the type of image where there are no light rays actually going to or coming from the image?
Virtual Image
Virtual Image Definition
An image formed by rays that appear to be coming from a certain position, but are not actually coming from this position; image does not form a visible projection on a screen.
What are the four characteristics of an image?
-Its location (closer than, farther than, or the same distance as the object to the mirror).
-Orientation (Upright or inverted)
-Size (Same size, larger than, or smaller than the object)
-Type (Real image or virtual image)
What are the characteristics of an image in a plane mirror?
-Same distance from the mirror as the object.
-Same orientation as object (Upright)
-Same size as the object
-Virtual
Concave Mirror Definition
A mirror whose reflecting surface curves inward.
True or False: You can draw a normal at a point on a curved surface by applying the same rules of reflection for a plane mirror by thinking of the curved surface as many small, flat mirrors.
True
What is the point at which all the normals meet called?
The Centre of Curvature
What is the thick horizontal normal that touches the centre of the mirror called?
The Principal Axis
Principal Axis Definition
On a concave mirror, the line that passes though the centre of curvature of the mirror, and is normal to the centre of the mirror.
What is the point at which the principal axis cuts the centre of the mirror called?
The Vertex
Focal Point Definition
The point on the principal axis through which reflected rays pass when the incident rays are parallel to and near the principal axis.
Focal Length Definition
The distance between the vertex of a mirror and the focal point; half the distance from the vertex to the Centre of Curvature.
What is the type of image called where the rays actually meet at the image?
Real Image
Real Image Definition
An image that is formed when reflected rays meet.
What are the characteristics of an Image for an Object between F and a Concave Mirror?
-Farther from the mirror than the object.
-Upright
-Larger than object
-Virtual
What are the characteristics of an Image for an Object between F and C?
-Farther from the mirror than the object (beyond C).
-Inverted
-Larger than object.
-Real
What are the characteristics of an Image for an Object beyond C?
-Closer to the mirror than the object (Between C and F).
-Inverted
-Smaller than object
-Real
What does the magnification of an image tell you?
The size, or height, of the image relative to the object using object and image distances.
Magnification Definition
The change in size of an optically produced image.
Spherical Aberration Definition
Irregularities in an image in a curved mirror that result when reflected rays from the outer parts of the mirror do not go through the focal point.
Convex Mirror Definition
A mirror whose reflecting surface curves outward.
What are the characteristics of an Image for an Object in a Convex Mirror?
-Closer to the mirror than object (between the mirror and F).
-Upright
-Smaller than object.
-Virtual
How to Draw a Ray Diagram for Image in Concave Mirror (3 Points)
-Incident ray parallel to principal axis is reflected through focal point.
-Incident ray through focal point is reflected parallel to principal axis.
-Incident ray through C is reflected back through C.
How to Draw a Ray Diagram for Image in Convex Mirror (3 Points)
-Incident ray parallel to principal axis is reflected as if it came from f.
-Incident ray heading to focal point is reflected parallel to principal axis.
-Incident ray heading to C is reflected back along incident ray
Characteristics of Images Based on Results from Calculations
Location: Depends on if image distance is greater or less than object distance
Orientation: Image height is Positive if Upright; Image height is Negative if Inverted
Size: Depend on if image height is greater or less than object height.
Type: Real if image distance is positive; Virtual if image distance is negative
