Wilhelm Wien discovered that... Question 5 options: the amount of blue-shifting or red-shifting that a wave of light undergoes from its normal wavelength is directly proportional to the radial velocity of its source towards or away from the observer. of all the EM wavelengths that an object emits, the most strongly emitted wavelength is dependent on the temperature of that object. objects radiate EM waves more intensely across the entire spectrum as they become hotter. different frequencies (colours) of light can be thought of as particles of light (photons) containing different amounts of energy