# Doppler Effect Formula

## Doppler Effect Formula

Doppler Effect Formula is essentially a characteristic of sound waves. In the Extramarks article, Doppler Effect Formula, students will learn about this Doppler Effect Formula and discover how to apply the Doppler Effect Formula. After that, the student will be able to quickly and easily compute the Doppler Effect Formula in a variety of circumstances.

The notes and solutions based on the Doppler Effect Formula have been compiled by some of the top subject-matter experts working in collaboration with Extramarks to make learning easier and fun for students.

The Doppler Effect Formula notes and solutions are extremely student-friendly, dynamic, diverse and varied in nature. Experts have made sure that the Doppler Effect Formula notes are updated according to the CBSE and NCERT syllabus and pertain to the framework of the NCERT books.

The Hindi version of the Doppler Effect Formula notes and solutions has been compiled by some of the most skilled translators at Extramarks. The Doppler Effect Formula solutions can be used by students to take personal notes.

### Definition

The Doppler Effect Formula, also known as Doppler shift, is the term used to describe how movement alters the frequency of sound waves. Consider the scenario where a police car is zooming past you while you are standing on the pavement. Do you notice how the siren’s tone varies as it moves a certain distance? As it gets closer to you, the volume increases, but there is another aspect of the sound that changes. The pitch of the car increases as it approaches you and decreases as it pulls away. The frequency of the waves, or how many waves travel through an area in a given amount of time, determines how the pitch changes.

Students can find a more detailed explanation of the Doppler Effect Formula that has been given on the Extramarks website and mobile application.

### Doppler Effect Formula

If the source of the sound and the listener are moving apart from one another, the sound that the listener hears will also vary. The Doppler Effect Formula is what it is. When the source and the listener are in proximity, the frequency heard by the listener is louder than the sound the source produces.

The frequency that the listener hears is lower than the frequency of the sound from the source when the listener and the source are farther apart. Sound frequency is measured in Hertz (Hz). A cycle per second is equivalent to one Hertz here (1 Hz = 1 s-1 = 1 cycle/s.

As a result, the Doppler Effect Formula is presented as it is on the Extramarks website and mobile application for students to understand, comprehend and retain every bit of the Doppler Effect Formula.

### Solved Example for You

Question

A motorist is driving down a road adjacent to some railroad rails. The train’s horn, which produces a sound with a single frequency of 420.0 Hz when it approaches, blows. The train is moving at a speed of 32.0 m/s while the driver is travelling at 18.0 m/s. The sound also travels at a speed of 340.0 m/s. Determine the sound frequency that the car’s driver will hear.

Answer: Students must first build a coordinate system in order to find the frequency. According to this theory, progress is made from the source to the listener. The train’s horn is the source, hence the train’s velocity is negative while the driver’s automobile velocity is positive. V = 340.0 m/s, vL = 18.0 m/s, vs = 32.0 m/s, and fs = 420.0 Hz are the values that are now known to us.

In order to determine the frequency, we shall arrange the values in the Doppler Effect Formula as follows:

fL = 𝑣+𝑣𝑙𝑣+𝑣𝑠 fs

fL = 340.0𝑚/𝑠+18.0𝑚/𝑠

340.0𝑚/𝑠–32.0𝑚/𝑠 (420.0 Hz) (420.0 Hz)

fL = 358.0𝑚/𝑠308.0𝑚/𝑠 (420.0 Hz) (420.0 Hz)

fL ≅ (1.162) (420.0 Hz) (420.0 Hz)

fL ≅ 488.2 Hz