Kalics

  Conductors, Insulators and Semi-conductors, p-n Junction CLASSIFICATION OF MATERIALS:      On the basis of the ability of various materials to conduct current, the materials are classified as conductors, insulators and the semiconductors. Conductors : 1. A substance which is very good carrier of electricity is called conductor. 2. The term conductor is applied to any material that will support a generous     flow    of charge when a voltage source of limited magnitude is   applied            across its terminals. 3. The copper and aluminum are good examples of a conductor Insulators: 1. A very poor conductor of electricity is called as insulator. 2.   An insulator is a material that offers a very low level of conductivity under        an applied voltage . 3.     Glass, Wood, Mica, Diamond are the examples of an insulator. Se...

  Units and Measurement,Dimensions, Errors, Significant figures Units and Measurements    Physics is a quantitative science, where we measure various physical quantities during experiments. •A measurement always involves a comparison with a standard measuring unit which is internationally accepted. eg. measuring the mass of a given fruit we need standard mass units of 1kg, 500g,etc. • “The standard measure of any quantity is called the unit of that quantity. ’’ Requirements of Good Units: The unit must be 1. Invariable 2. Reproducible 3. Universally accepted       There are large number of physical quantities which we have to study in physics, these quantities are broadly divided into two types. 1 Fundamental Physical quantities 2 Derived Physical quantities Fundamental Quantities and Units: •Fundamental Quantity: A quantity which does not depend on any other physical quantity is    called as fundamental quantity. ...