🔬 Physics experiments
Lenses and ray diagrams
Move the object; see where the image forms and why.
💬 Questions and answers
1What am I looking at?
Answer: A convex or concave lens with an object and its image on the principal axis.
2What are its parts? (click a part to identify it)
Answer: Lens, principal axis, focus (F), 2F, object, image and two rays.
3How does it work?
Answer: A ray parallel to the axis passes through (or appears to come from) the focus after refraction; a ray through the optical centre goes straight. Where they meet is the image.
4Why is it important?
Answer: Lenses are used in spectacles, cameras, microscopes and projectors.
5What happens if I change something? (use the sliders)
Answer: Move the object or change the focal length; the image position, size and nature update.
6What should I remember for the exam?
Answer: 1/v − 1/u = 1/f; magnification m = v/u. Convex lens with object beyond 2F gives a real, inverted, diminished image between F and 2F. Concave lens always gives a virtual, erect, diminished image.