Law of reflection is applicable to only smooth surfeces not on rough surfaces .Because n rough surfaces it light rays reflected in arbitrary directions and so no law can be derived for it . So law of reflection for smooth surfaces does not hold good in case of rough surface.In the trasparent surface there are another property shown by light rays that is called refraction. Although reflection also takes place from the surface ,but is not important as compare to refraction. You will learn convex lense and concave lense which is transparent surface. There are both properties shown by light rays reflection and refraction .