The Doppler effect indicates that the frequency of energy (sound or light) waves when an object is approaching and when an object is moving away?

The Doppler effect is the change in frequency of waves (such as sound or light) due to the relative motion between the source of the waves and the observer. When an object is approaching, the waves are compressed, causing a higher frequency, resulting in a higher pitch for sound waves or a blue shift for light waves. When an object is moving away, the waves are stretched, causing a lower frequency, resulting in a lower pitch for sound waves or a red shift for light waves.