Ch. 15 Lenses and Refraction

Ch. 15 Lenses and Refractionpgs. 562 – 586

Chapter summary pg. 586

• Lens– A transparent object that refracts light rays– Images are formed through the refraction

of light– Two types:

Convex lens Concave lensConverging lens Diverging lens

• Focal point for a convex lens is the image distance for an infinite object distance

• Lenses have a focal point on each side of the lens

Convex Lens Images

Convex Lens Images

Convex Lens Images

Convex Lens Images

Convex Lens Images

Convex Lens Images

• A Simple Magnifier enables you to examine small objects by producing an enlarged image

• It increases the angular size of an object– Angular size increases when the object

moves closer– Angular size decreases when the object

moves farther away

Concave Lens Image• Diverging lenses only produce one

kind of image

• Positive magnification = image is upright and virtual• Negative magnification = image is real and inverted

M< 1, image is smallerM = 1, image is the same sizeM > 1, image is larger

An object is placed 30.0 cm in front of a converging lens with a focal length of 10.0 cm. Find the image distance and the magnification. Describe the image.

An object is placed 12.5 cm in front of a diverging lens with a focal length of

10.0 cm. Find the image distance and magnification. Describe the image.