Question

Explain what is Doppler effect in sound and state its any four applications.

Answer 1

The Doppler effect is the apparent shift in wave frequency due to the movement of the wave source. The Doppler effect explains why we perceive a change in pitch of the sound of a passing siren. It also explains the presence of shock waves and sonic booms when observing a super sonic aircraft.

Applications

$\left(a\right)$ Flow measurement-Instruments such as Lase doppler velocimeter(LDV), and Acoustic doppler velocimeter(ADV) have been developed to measure velocities in in a fluid flow.

$\left(b\right)$ Satellite communication-Fast moving satellites can have a doppler shift of dozens of kilohertz relative to a ground station.

$\left(c\right)$ Sirens-The siren on a passing emergency vehicle will start out higher than its stationary pitch, slides down as its passes, and continue lower than its stationary pitch as it recedes from the observer.

$\left(d\right)$ Radar-The Doppler effect is used in some type of radar. , to measure the velocity of detected object