Psychophysics is the branch of psychology that is concerned with the effect of physical stimuli on mental processes such as sensation and perception. Weber is considered to be the father of psychophysics and he, along with Fechner is considered as a central figure the history of the development of this branch. Both contributed to set the foundation of psychophysics and provided a law that gives the concept of measuring the abilities of discriminating intensities of various stimuli (such as two lights, two sounds etc.). In all cases the result comes out to be the same i.e. a Just Noticeable Difference ...