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Spherical refracting surfaces - Six cases. Sign Convention to be used in the optics equations: The object distance p is positive for a real object. It would be negative for a virtual object, but that is a rare situation.
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Sign Convention to be used in the optics equations: • The object distance p is positive for a real object. It would be negative for a virtual object, but that is a rare situation. • The image distance i is positive for a real image and negative for a virtual image. • Radii of curvature get their sign based on whether the centers of curvature are on the “R-side” or “V-side”. From posted “Practical Rules” on Lecture Materials page:
V-side So r < 0 R-side, So i > 0 V-side R-side So r > 0 i > 0 Note: p > 0 since the object is real.
V-side So r < 0 i < 0 V-side So i < 0 R-side R-side So r > 0
V-side So i < 0 R-side So r > 0 V-side So r < 0 i < 0 R-side
Converging Lens (f > 0) Focal point Diverging Lens (f < 0)
Converging Lens f > 0 Focal point f < 0 Diverging Lens
Converging Lens f > 0 Focal point f < 0 Diverging Lens
R-side V-side V-side R-side R-side V-side Locating the Image (From posted “Practical Rules” on Lecture Materials page)
Magnifying glass Typical “near point” Angular magnification
Simple thin-lens microscope Not to scale. s = “tube length” The eyepiece acts as a magnifying glass for the image from the objective lens. The final magnification M is the product of the lateral magnification m of the objective lens and the angular magnification m of the eyepiece.
Angular magnification Refracting telescope ey Not to scale. A distant object subtends an angle ob. The virtual image viewed through the telescope subtends ey.
Eyeglasses myopic eye (shortsighted) corrected with diverging lens hyperopic eye (farsighted) corrected with converging lens