Total internal reflection and critical angle
Reflection and refraction · Physics
Convex lens ray diagram
Interactive 3DMove the object and watch parallel rays converge at the focal point while the image obeys 1/f = 1/v + 1/u.
Controls
Drag the sliders or type a value — the simulation updates live.
cm
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Study notes
A convex lens has focal length f = 10 cm. An object stands 30 cm away. 1/v = 1/f − 1/u = 1/10 − 1/30 = 2/30 → v = 15 cm. The image forms 15 cm beyond the lens. Magnification m = −v/u = −15/30 = −0.5: the image is real, inverted, and half the object's size. Move the object inside f (say 5 cm) and the image becomes virtual, upright and magnified — a magnifying glass.