In this chapter we will go through the definitions of light, reflection of light, some general terms related to reflection of light and laws of reflection. Then we will go through the plane mirror and the characteristics of images formed by plane mirror. After this we will go through the spherical mirrors ( concave and convex mirror ) – formation of images by spherical mirrors , mirror formula and magnification. After this we will go through the concept of refraction , laws of refraction.Then we will deal with the lenses , types of lenses , formation of images by spherical lenses , lens formula and magnification. Finally we will deal with the power of lens.