Correct Answer - Option 2 : Doppler effect.
The correct answer is option 2.
- The Doppler effect is the change in frequency or wavelength of a wave in relation to an observer who is moving relative to the wave source.
- The Doppler effect is observed whenever the source of waves is moving with respect to an observer.
- The Doppler effect can be described as the effect produced by a moving source of waves in which there is an apparent upward shift in frequency for observers towards whom the source is approaching and an apparent downward shift in frequency for observers from whom the source is receding.
∴ Hence the correct answer is the Doppler effect.
refers to the change in wave frequency during the relative motion between a wave source and its observer. For instance, when a sound object moves towards you, the frequency of the sound waves increases, leading to a higher pitch.