<prompt> Weber Fechner Law is:Magnitude of stimulus strength perceived is approximately propoionate to the log of the intensity of stimulus strengthMagnitude of stimulus strength perceived is directly propoional to the intensity of stimulus strengthThreshold of receptor is directly propoional to stimulus strengthThreshold of receptor is inversely propoional to stimulus strength  <response>: Magnitude of stimulus strength perceived is approximately propoionate to the log of the intensity of stimulus strength Weber - Fechner law It states that the magnitude of the sensation felt in propoionate to the log of intensity of the stimulus. Example - A person holding 30 grams weight in his hand can barely detect a I gm rise in weight a rise than 1 gm would not be detectable. But when he holds 300 gm of weight. he can rarely detect a 10 gm increase in weight a rise less than 10 gm would not be detectable to him. So a 300 gm wt. and Say 307 gm of weights would appear same to him. This is expressed mathematically as Interpreted signal strength Log x stimulus intensity constant 