Question

what is Doppler Effect
give examples and
write the uses of Doppler Effect

Answer 1

Hey friend!!
The answer is.....

✍Definition: Doppler Effect refers to the change in wave frequency during the relative motion between a wave source and its observer. It was discovered by Christian Johann Doppler who described it as the process of increase or decrease of starlight that depends on the relative movement of the star.

✍Examples:
 ⏩Doppler Effect works on both light and sound objects. For instance, when a sound object moves towards you, the frequency of the sound waves increases, leading to a higher pitch. Conversely, if it moves away from you, the frequency of the sound waves decreases and the pitch comes down. The drop in pitch of ambulance sirens as they pass by and the shift in red light are common examples of the Doppler Effect.

⏩Edwin Hubble made the discovery that the universe expands as a consequence of the Doppler Effect. It has important applications in the fields of astronomy and space technology.

⏩The use of Doppler Effect in astronomy in relation to light waves depends on the fact that the spectra of stars are not constant. Different stars exhibit different absorption lines at defined frequencies, but Doppler Effect is identifiable only when these absorption lines are away from these defined frequencies.

✍There are various applications of Doppler Effect. It is used in:

1. Sirens

2. Astronomy

3. Radars

4. Medical imaging and blood flow management

5. Flow management

6. Velocity profile management

7. Satellite communication

8. Audio

9. Vibration measurement

I hope it helps you.....

Answer 2

$\huge{hey }$

$\huge{ \mathfrak{here \: is \: answer}}$

DOPPLER'S EFFECT
Non - Relativistic Treatment
As most readers must have read in physics according to. This phenomenon the pitch sound observed by an observer is different in two cases, firstly when both the source and observer are stationary and secondly when there is relative motion between them. When source and observer are approaching each other, the apparent frequency is increased and when receding, decreased. This phenomenon is called doppler's effect which occurs with all kinds of wave motion, although in case of mechanical waves involving a material medium, its nature is some what different from the case of electromagnetic waves such as light where no medium is involved . In the case of light waves, if spectrum is observed in a spectrometer, a shift in the position of spectral line from the original position is observed with the motion of source.

we first consider the case when the observer is at rest and the source is moving towards it velocity u. let the frequency of the source be f so that the time period
T=1/f
and the wave speed be c in a time time interval T during which one cycle of wave is emitted the wave progresses a at distance cT but in the same period the source wave in the same direction distance u T hence wavelength which is distance between two successive maximum in the wave is cT-uT instead of cT.
Hence the corresponding frequency denoted by f1' its given by

f1'= c/ T(c-u)= cf/c-u

= f/ 1-(c/u)........ (1)

which represents and Apparent increase in the frequency if the source is moving away from the observer we put - u in place of u in equation( 1st) and get the corresponding f1'

in the second case When the source is stationary but the observer is moving with the velocity v from the source the wave is speed relative to the observer is not c but c-v and hence apparent frequency in the case is.

$f \tiny{2} = \frac{c - v}{ \lambda}$
= c-v/c/f
= c-v/c*f

$1 - \frac{v}{c} f \: .......(2)$

now both observer and source are moving

$\bf{\lambda \tiny{1} = \frac{c}{f \tiny{1}} } = \: \frac{c - u}{ \lambda}$

$\huge \boxed { \boxed{ \boxed{hope \: it \: helps}}}$

$\huge{ \mathfrak{thanks}}$