# Doppler Effect Calculator

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## What is Doppler Effect Calculator?

A Doppler Effect Calculator is a tool that helps calculate the frequency shift of a sound wave due to the relative motion between the source and the observer. The Doppler effect is observed in various real-life scenarios, such as the change in pitch of a siren when an ambulance passes by or the change in frequency of electromagnetic waves emitted by stars. A Doppler Effect Calculator uses a mathematical formula to calculate the frequency shift.

## Formula

The formula for calculating the frequency shift due to the Doppler effect is as follows:

**f = f0 * (v + vr) / (v + vs)**

**Where:**

- f is the observed frequency
- f0 is the emitted frequency
- v is the speed of sound in the medium
- vr is the velocity of the receiver (observer) relative to the medium
- vs is the velocity of the source relative to the medium

## Example

Suppose a car with a horn is moving towards an observer at a speed of 30 m/s. The horn emits a sound wave with a frequency of 500 Hz, and the speed of sound in air is 343 m/s. What is the frequency of the sound wave observed by the observer?

**Given:**

- f0 = 500 Hz (emitted frequency)
- v = 343 m/s (speed of sound in air)
- vr = 0 m/s (velocity of observer relative to the medium)
- vs = 30 m/s (velocity of source relative to the medium)

Using the Doppler effect formula, we get:

f = 500 * (343 + 0) / (343 + 30) = 522.47 Hz

Therefore, the frequency of the sound wave observed by the observer is 522.47 Hz.

## How to use the calculator

To use a Doppler Effect Calculator, enter the values of the emitted frequency (f0), speed of sound in the medium (v), velocity of the receiver (vr), and velocity of the source (vs) into the calculator. Then, click on the “Calculate Frequency” button, and the calculated frequency shift (f) will be displayed on the screen.

## FAQs

What is the Doppler effect?

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.

How does the Doppler effect apply in real-life scenarios?

The Doppler effect is observed in various real-life scenarios, such as the change in pitch of a siren when an ambulance passes by or the change in frequency of electromagnetic waves emitted by stars.

Can the Doppler effect be observed for light waves?

Yes, the Doppler effect applies to light waves as well, and is commonly used in astronomy to study the motion of celestial bodies.