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# Tag Archives: doppler effect

## Calculating velocity of an approaching vehicle

Is it possible to design a device that calculates the velocity of an approaching vehicle if the speed of sound in air at that location  is known?

Such a device is already in use. It is based on a phenomenon called Doppler Effect.

Get the details at the following Links.

1. www.physicsclassroom.com/class/waves/u10l3d.cfm
2. science.howstuffworks.com/science-vs-myth/everyday-myths/doppler-effect3.htm
3. http://en.wikipedia.org/wiki/Doppler_effect

## LCD & Doppler effect

1. what is liquid crystal display
2. What is Doppler Effect ? ? ?

Ans:

LCD stands for Liquid Crystal Display. It works on the principles of polarization. By the selective alignment of liquid crystals light is blocked or allowed making the display transparent.

## Wave travelling from one medium to another

“when a wave enters from air to water, its wavelength changes but

frequency remains unchanged. why”

Velocity of a wave = frequency x time period

V = ν λ

When a wave travels from one medium to another, its velocity changes and so also is its wavelength, but frequency; which is the number of vibrations produced per second is independent of the medium, remains constant.

However, their is a phenomenon called Doppler Effect where the apparent frequency (observed frequency) is different from actual frequency and is caused by the relative movement between the source and observer (listener)

## Doppler Effect

“What is Doppler Effect?”

Doppler Effect is the apparent change in frequency of a wave due to the relative motion between the source and the listener.

(Please come back soon for more details with figures and videos)

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