Refraction of Light EM lesson 8 Convex converging Lens Thicker in the center than at the edges Have positive focal lengths Converge parallel rays of light that pass through them Rules for convex lenses ID: 468869
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Slide1
Converging and Diverging Lenses
Refraction of Light
EM lesson 8Slide2
Convex
(converging) Lens
Thicker in the center than at the edges
Have positive focal lengths Converge parallel rays of light that pass through themSlide3
Rules for convex lenses
If an object is beyond
C,
the image is real, inverted, and smallerIf the object is at C (or 2F), the image is real, inverted, and the same size as the object
If the object is between C and F, the image is real, inverted, and enlarged.
If the object is at F, no image is formedSlide4
Eg) An object is placed 30 cm from a converging lens which has a focal length of 10.0 cm. Indicate where the image is located
.Slide5
Virtual Images Formed By a Convex Lens
A
virtual image
is formed if the object is located between the focus and the lens.Slide6
Virtual Image
if object is between F and the lens, image formed is virtual, upright and larger
F
FSlide7
Eg) a bug is 6.00 cm from a convex lens that has a focal length of 8.00 cm. Determine the image distance
.Slide8
Concave (diverging)
Lens
Thinner at the center than the edges
Have negative focal lengths and diverge parallel rays of light passing through them
The focal length depends on the index of refraction and curvatureSlide9
Note:
As n (index of refraction) increases, focal distance decreases
As curvature increases, focal distance decreases alsoSlide10
Concave Lenses and Virtual Images
concave lens will only produce a virtual image
F
Image formed is virtual upright and smaller than original objectSlide11
Eg) A diverging lens has a focal point of -5.00 cm. If an object is placed 10.0 cm from the lens, what is the image distance?Slide12
Review of Lenses
to tell whether an object is real or virtual, erect or inverted, enlarged or diminished – DO THE MATH
Real image –
di > 0Virtual image – di < 0
Erect image – hi > 0Inverted image – hi
< 0Enlarged image – M > 1Diminished image – M < 1Slide13Slide14