Mirrors : Mirrors Reflection : Light always travels in a straight line
However, when light hits another substance, it will change direction
Is a material is opaque (not transparent or translucent; impenetrable to light; not allowing light to pass through.), the light will not pass through it but bounce off
The change in the direction of light is called reflection. Reflection Texture of the Surface : The manner in which the light reflects depends on the surface’s smoothness
Light that hits a rough surface is reflected in many directions. This is called diffuse reflection.
Light reflected off a smooth surface is called specular reflection. Texture of the Surface Reflected Angles : Angle of Incidence: The angle between a ray that strikes a surface and the normal to that surface at the point of contact. Reflected Angles Angle of Reflection : Angle of Reflection: The angle formed by the line normal to a surface and the direction which a reflected ray moves.
Go to the following link for an animation Angle of Reflection http://www.glenbrook.k12.il.us/gbssci/phys/mmedia/optics/lr.html Incoming and reflected angles : Incoming and reflected angles are equal
Law of Reflection: The angle of incidence= the angle of reflection Incoming and reflected angles Reflection Rules : The image is said to be a virtual image
Left right reversal: if you raise your left hand, you will notice that the image raises what would seem to be it's right hand.
Image is upright instead of inverted- there is no top-bottom vertical reversal. If you stand on your feet in front of a plane mirror, the image does not stand on its head.
For plane mirrors, the object distance (often represented by the symbol do) is equal to the image distance (often represented by the symbol di).
the dimensions of the image are the same as the dimensions of the object. If a 1.6-meter tall person stands in front of a mirror, he/she will see an image which is 1.6-meters tall. Reflection Rules Concave Mirrors : A concave mirror is an inwardly curved mirrored surface that is a portion of a sphere that converges (come together) incoming light.
Concave mirrors create a magnified image
How big the image appears depends on how curved the mirror
R= radius of curvature
C= center of curvature Concave Mirrors Real Images : A real image is an image formed when rays of light actually intersect at a single point
A real image is a clear and crisp image that is formed
Image location can be predicted from the mirror equation: 1/p + 1/q = 1/f
P= object distance, q= image distance, f= focal length Real Images Calculating magnification : Unlike flat mirrors, the images formed are not the same size as the original image.
How big or small they appear can be calculated by the following equation:
h’= image height
h= object height
q= image distance
p= object distance Calculating magnification Convex Mirrors : Convex mirrors are outwardly curved mirrors that is a portion of a sphere that diverges incoming light rays
The image appears smaller
The focal point and center of curvature are behind the mirror’s surface
A virtual, upright image forms where three rays meet
Magnification for convex mirrors is always less than 1. Convex Mirrors Concave vs. Convex mirrors : Concave vs. Convex mirrors Convex mirror images : Convex mirror images Telescopes : One type of telescope uses curved mirrors and small lenses to form an image. This is called a reflecting telescope.
Another type of telescope uses only lenses to form an image and is called a refracting telescope Telescopes