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In optical instrument, the lenses are used to form image by the phenomenon of
Explanation
In optical instruments, lenses form images primarily through the phenomenon of refraction. Refraction is the bending of light as it passes from one transparent medium into another, such as from air into glass, due to a change in the speed of light. Lenses, which are made of transparent materials with curved surfaces, utilize this property to either converge or diverge light rays to form real or virtual images [1]. While mirrors form images through reflection, lenses are specifically designed to obey the laws of refraction. This fundamental principle allows optical instruments like cameras, telescopes, and microscopes to focus light and magnify objects. Other phenomena like scattering involve unpredictable changes in direction, and diffusion refers to the spreading of light, neither of which is the primary mechanism for image formation in standard lenses.
Sources
- [1] Science , class X (NCERT 2025 ed.) > Chapter 9: Light – Reflection and Refraction > 9.3.4 Image Formation by Lenses > p. 152