optics: mirrors and lenses 2
DESCRIPTION
Optics: Mirrors and Lenses 2. Convex Mirrors. Rays diverge so the image is virtual f is half of the radius of curvature (negative) Image is virtual, erect and reduced Wide area reflected so used in stores, rear view mirrors, side view mirrors (objects in mirror…). Lenses. - PowerPoint PPT PresentationTRANSCRIPT
Optics: Mirrors and Lenses 2
Convex Mirrors Rays diverge so the image is virtual f is half of the radius of curvature
(negative) Image is virtual, erect and reduced Wide area reflected so used in
stores, rear view mirrors, side view mirrors (objects in mirror…)
Lenses Glass or Plastic or Polycarbonate with
n greater than 1 2 sides (faces) of the lens
Each side can be flat OR part of a sphere
Convex and Concave Lenses Convex
thicker at the center than the edgesConvergingRefract light rays so they meet
Convex and Concave Lenses Concave
Thinner at the center than the edgesDiverging
Covex Lens: Real Image 3 ray diagram – from top of object
First ray parallel to axis, then through focal point
Second ray through F’ then parallel to axisThird ray is through center of lens
Lens assumed very thin f depends on
Shape of lensn of lens material
Covex Lens: Real Image Beyond 2F – image real, inverted, and
reduced Approaching F – image real, inverted
enlarged At 2F image is at 2F – inverted, same
size
Covex Lens: Virtual Image
If the object is at F, ray emerge in a parallel beam
If the object between F and lens then the rays
DO NOT converge on opposite side of lensimage is virtual, erect and enlarged
Concave Lens: Virtual Image All rays diverge Virtual image is erect and reduced
Doesn’t matter how far object is from the lens
f is negative, corrects near sightedness