W
 Work: If the applied force on object leads to some displacement then it is said that work is done on object. Work-energy theorem: The work done by the resultant net force acting on a body is equal to change in its kinetic energy. Weidmann-Franz law: The linear dependence of “ratio of thermal conductivity to elctriacl conductivity” on absolute temperature is known as Weidmann-Franz law. The ratio is directly proportional to absolute temperature. Welding: Process of permanently joining two similar metals by localized fusion by applying suitable heat and pressure. Wien’s Displacement law: The wavelength of radiation emitted by a black body at any temperature is inversely proportional to absolute temperature of the body. (or) At any temperature, the energy of radiations of wavelength emitted by black body is directly proportional to fifth power of its absolute temperature. Wave: Wave is pattern and doesn’t have any physical existence. Wave motion comprises of patterns repeating at regular intervals and thus wave travels with uniform velocity. Wave length: Distance travelled by the wave in the time in which particle of medium completes one vibration. (or) Distance between two nearest particles in the same phase.