Lenses
Lenses refract light to form images, with convex lenses converging light and concave lenses diverging light, following specific formulas.
Core concept
The lens formula, 1/v - 1/u = 1/f, relates object distance (u), image distance (v), and focal length (f) for both convex and concave lenses.
How it works
Convex (converging) lenses can form real or virtual images depending on object position, used in magnifying glasses, cameras, and correcting long-sightedness.
Why it matters
Concave (diverging) lenses always form virtual, diminished, upright images, commonly used to correct short-sightedness (myopia).
Key detail
Magnification (m=v/u) tells us how much larger or smaller the image is compared to the object, useful in optical instrument design.
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Quick notes
• Lens formula: 1/v - 1/u = 1/f.
• u=object distance, v=image distance, f=focal length.
• Convex lenses converge light.
• Form real or virtual images, correct long-sightedness.
• Concave lenses diverge light.
• Always form virtual, diminished images.
• Correct myopia (short-sightedness).
• Magnification: m=v/u.