Notes and Study material for Exams
Measurement of any physical quantity involves comparison with a certain basic, arbitrarily chosen, internationally accepted reference standard called unit. The result of a measurement of a physical quantity is expressed by a number (or numerical measure) accompanied by a unit. A unit of measurement is a definite magnitude of a quantity, defined and adopted by … Read more
Holography Holography, means of creating a unique photographic image without the use of a lens. The photographic recording of the image is called a hologram, which appears to be an unrecognizable pattern of stripes and whorls but which—when illuminated by coherent Light, as by a laser beam—organizes the light into a three-dimensional representation of … Read more
Simple Telescope And Astronomical Telescope, Construction working, uses, ray diagram Simple telescope A simple working telescope requires nothing more than a pair of lenses mounted in a tube. The lens in front, known as the objective, focuses an image; the lens in back, known as the eyepiece, magnifies the image. Although it may seem like … Read more
Conductors, semiconductors and insulators Materials are classified as conductors, insulators, or semiconductors according to their electric conductivity. The classifications can be understood in atomic terms. Electrons in an atom can have only certain well-defined energies, and, depending on their energies, the electrons are said to occupy particular energy levels. In a typical atom with many … Read more