Why can a magnifying glass make text look bigger, and where must I hold it?
A magnifying glass is a convex lens.
A magnifying glass is a convex lens. Held so the text is within its focal length, it forms an enlarged, upright, virtual image you see through the lens — that's magnification. Move it beyond the focal length and the image flips to real and inverted (as on a screen). So keep the object closer than f for a bigger, right-way-up view.
Key point
Object within the focal length of a convex lens → enlarged upright virtual image.
Common mistake
expecting magnification at any distance from the lens.
Memory tip
keep the text inside f — cross f and the image inverts.
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