Thin Lenses An Application of Refraction There are

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Thin Lenses An Application of Refraction

Thin Lenses An Application of Refraction

There are 2 basic types of lenses A converging lens (Convex) takes light rays

There are 2 basic types of lenses A converging lens (Convex) takes light rays and bring them to a point. A diverging lens (concave) takes light rays and spreads them outward.

General Terms Focal point – point where distant light rays will converge or diverge

General Terms Focal point – point where distant light rays will converge or diverge from Focal length – the distance from the center of the lenses to the focal point. Principal axis – horizontal plane that cuts the lens in half.

General Terms Magnification – ratio of image to object Object distance – distance from

General Terms Magnification – ratio of image to object Object distance – distance from object to center of lens. Image distance – distance from image to center of lens.

Types of images Real images – occur when actual light rays intersect. Image can

Types of images Real images – occur when actual light rays intersect. Image can be projected onto a screen. Occur on the opposite side of the lens from the object. Virtual images – light rays never intersect. Image cannot be projected onto a screen. Occur on the same side of the lens as the object.

Types of Images Real images Virtual Images + di, -M, -hi - di, +M,

Types of Images Real images Virtual Images + di, -M, -hi - di, +M, +hi Always inverted (below prin axis) Always upright (above prin axis) Only produced by converging lens Produced by both converging and diverging lenses

Positive vs. Negative The object is always on the positive side of the lens

Positive vs. Negative The object is always on the positive side of the lens ( object distance (do) is always positive). Anything on the opposite side of the lens from the object is positive. Anything on the same side of the lens as the object is negative. Above the principal axis is positive; below negative.

Converging Lenses Produce real or virtual images. If do > focal length, then image

Converging Lenses Produce real or virtual images. If do > focal length, then image is real. Focal point is (+) for calculations. (converge at + focal point) Example Sketch:

Diverging Lenses Produce on virtual and reduced images. Focal point is (-) for calculations

Diverging Lenses Produce on virtual and reduced images. Focal point is (-) for calculations (diverge from – focal point). Light rays never actually intersect. Example Sketch:

Thin Lenses Equations 1/f = 1/do + 1/di M = - di / do

Thin Lenses Equations 1/f = 1/do + 1/di M = - di / do or hi / ho Keep track of positive and negative values.

Examples An object is placed 35 cm in front of a converging lens with

Examples An object is placed 35 cm in front of a converging lens with focal length of 20 cm. Calculate the image’s position relative to the lens as well as the image’s characteristics.

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Optics 2 REFRACTION LENSES REFRACTION Refraction is theOptics 2 REFRACTION LENSES REFRACTION Refraction is the
REFRACTION Refraction Refraction of Light Refraction the bendingREFRACTION Refraction Refraction of Light Refraction the bending
Refraction and Thin Lenses We can use refractionRefraction and Thin Lenses We can use refraction
Refraction and Thin Lenses We can use refractionRefraction and Thin Lenses We can use refraction
Thin Lenses Ray Tracing Thin Lenses Ray TracingThin Lenses Ray Tracing Thin Lenses Ray Tracing
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CONTACT LENSES CONTACT LENSES CONTACT LENSES Optical devicesCONTACT LENSES CONTACT LENSES CONTACT LENSES Optical devices
Lenses Diverging and Converging Lenses Double Convex lensesLenses Diverging and Converging Lenses Double Convex lenses
Lenses Refraction of Light Lenses Word bank LENSLenses Refraction of Light Lenses Word bank LENS