Estimation of constants of thermal radiation using tungsten filament bulb.

Abstract

Abstract The concept of black body is of primary importance in studying the energy transfer of thermal electromagnetic radiation at all wavelengths. Several physical bodies like incandescent lamps, electric heaters, stoves, the sun and the other stars, microwave background radiation, etc, are considered to be black bodies as their radiation spectra fits the black body radiation curve. The planck’s constant h , quantises the energy emitted by a black body in integral multiples of h ν , ν being the frequency of the emitted radiation. We present here an experiment using a low cost apparatus to estimate the value of Planck Constant by studying the radiation of a 40 W tungsten filament bulb within the accuracies of 10%. Such an experiment can be easily implemented in undergraduate college laboratories. The experiment can also be used to verify the Stefan-Boltzmann law and Wien’s displacement law.