Evolution and Classification Similarities among organisms allow us to group them and then study the groups. Characteristics are details of appearance or behavior; or a particular form or a particular function. Some basic characteristics will be shared …

Reflection of Light Light is a form of electromagnetic radiation that causes in us a sensation of sight. It also provides us means of communication through optical fiber cables. Several phenomena taking place in nature can be explained by understanding …

Refraction of Light When light travels from one medium to another, there is a change in its direction due to a change in speed of light. Consider a pencil that is partly immersed in water. The light reaching us from the portion of the pencil inside wate…

Defects of Vision Sometimes, the eye may gradually lose its power of accommodation due to which the person cannot see the objects distinctly and comfortably. The defects of vision are described below: Myopia Myopia is also known as near-sightedness. A p…

The Human Eye Optical instruments, including our eyes, extend the range of our vision and enable us to see objects varying in size from very tiny, nearby objects to very large, distant objects, in this chapter we shall study about the human eye and opti…

Dispersion of White Light By A Glass Prism When white light is incident on a glass prism, it splits into a band of colours as the refracting surfaces of the glass prism are inclined at an angle. Example 1. Case Based: Take a thick sheet of cardboard and…

Atmospheric Refraction Atmospheric refraction is the refraction of light by the earth’s atmosphere due to the decrease of refractive index with decreasing density or increasing temperature of air. Apparent Position of Stars The stars appear slightly hig…

Scattering of Light: The phenomenon of change in the direction of light on striking an obstacle like an atom, a molecule, dust particle, water droplet etc is known as scattering of Light. It involves bouncing off electromagnetic radiation by atoms/molec…

Electric Current and Circuit Electricity is a form of energy and can be readily transmitted over large distances with relatively small loss in energy. In this chapter we will discuss about electric circuits, potential difference and flow of current in a…

Electric Potential The electric potential at a point is defined as the work done in moving a unit positive charge from infinity to that point. Potential Difference Potential Difference between two points on a conductor carrying current is defined as the…