The branch of physics dealing with the properties and behaviour of light is called optics. Light is a form of energy which helps us to see the objects.
Have you ever wondered why we are able to see the different objects around us, their images in a mirror , in a pond? This is simply due to reflection of light .
When light travels obliquely from one transparent medium into another it gets bent. e.g. This bending of light is called refraction of light. The straw appears to break at the surface of the water due to refraction of light. As light passes from air to water, its speed slows down and the light rays are bent.
Speed of light is different in different optical mediums.
Refractive Index is a characteristic property of a medium. The refracting ability of a medium is measured by its refractive index. Those with higher values of refractive index are optically denser than those with lower values of refractive index. e.g. water is optically denser than air but optically rarer than glass.
Learn about lenses - concave and convex and their image formation. Solve the problems related to lens, their image formation and refraction.
Learn the dispersion of white light through a prism and how a spectrum is formed. The phenomenon of splitting of white light by a prism into its constituent colours is known as dispersion.
The band of colours obtained on a screen on passing white light through a prism, is called spectrum. Do you know why we cannot see the whole spectrum ?
Learn about different optical instruments- simple microscope, astronomical telescope.