Light – Reflection and Refraction

This chapter studies how light behaves when it is reflected by mirrors and refracted by lenses. We revisit the laws of reflection and the images formed by plane mirrors, then study spherical mirrors (concave and convex) — their terms, ray diagrams, image formation, the New Cartesian sign convention, the mirror formula 1/v + 1/u = 1/f and magnification. We then take up refraction: bending of light, the rectangular glass slab, the laws of refraction (Snell's law), refractive index and its link to the speed of light, spherical lenses (convex and concave), the lens formula 1/v − 1/u = 1/f, magnification, and the power of a lens (dioptre). This is a formula- and diagram-heavy chapter worth strong marks in the Class 10 board exam.