Introduction In 1637 Desartes gave the corpuscular model of light derived Snell's law. It explained the laws of reflection and refraction of light at an interface. The corpuscular model predicted that if the ray of light (on refraction) bends towards the normal then the speed of lig…

Consider a thin p-types silicone (p- Si) semiconductor water. By adding precisely a small quantity of penravelent impurity, part of the p- SI wafer can be converted into n- Si. There  are several processes by which a semiconductor can be formed. The wafer now contains p- region and n- r…

The interplay of light with things around us gives rise to serveral beautiful phenomenona. The spectacle of colour that we see around us all time is possible only due to sunlight. The blue of the sky, white clouds, the red- hue at sunrise and sunset, the rainbow, the brilliant colours o…

It has been known for a long time that when a narrow beam of sunlight , usally called white light, is incident on a glass prism, the emergent light is seen to be consisting of several colour. There is actually a continuous variation of colour, but broadly, the different component colour…

Introduction A photocell is a technology application of the photoelectric effect. It is a device whose electrical properties are affected by light. It is also sometimes called an electric eye. A photocell consists of a semi- cylindrical photo- sensitive metal plate (emitter) and a wire …