my query is : The electric and magnetic fields don’t squeeze or stretch then how is Doppler Effect of light possible? In the phenomenon of Doppler Effect, light emitted from a moving source is detected to have different frequency. If this is taken on terms of detecting the no. of waves passing through the detector in one second it is fine. But according to the principle of relativity, the speed of light is a constant …. It does not change even if its source is moving…. And that means if still Doppler Effect is observed then the frequency, say, has got increased, then the wavelength should decrease to keep the speed of light constant. And as the wavelength appears to decrease though the original emitted one is larger….. it can be visualized as the wave has got squeezed due to its motion. But electric and magnetic fields don’t change their structure even when they are not stationary, i.e., they don’t stretch or squeeze….. Then how is the phenomenon of Doppler Effect of light observed?