GENERAL KNOWLEDGE

Detailed explanation-1: -The waves travel at the same speed, but the observed frequency depends on any relative motion between the observer and source. When the observed frequency changes, so does the wavelength. If the observer and source are moving toward each other, then the frequency increases and the wavelength decreases.

Detailed explanation-2: -Generally, the doppler effect can be defined as the change in wave frequency (whether it is light or sound) during relative motion between the source of the wave and the observer.

Detailed explanation-3: -Definition of the Doppler Shift: The Doppler shift is the alteration of the frequency observed of waves which occurs whenever the wave source is moving towards or away from the observer (or the observer is moving towards or away from the wave source).

Detailed explanation-4: -A higher frequency is received by the observer moving toward the source, and a lower frequency is received by an observer moving away from the source. In general, then, relative motion of source and observer toward one another increases the received frequency. Relative motion apart decreases frequency.