Doppler Effect

Physics ⇒ Waves and Sound

Doppler Effect starts at 11 and continues till grade 12. QuestionsToday has an evolving set of questions to continuously challenge students so that their knowledge grows in Doppler Effect. How you perform is determined by your score and the time you take. When you play a quiz, your answers are evaluated in concept instead of actual words and definitions used.

See sample questions for grade 11

A car horn emits a sound at 600 Hz. The car moves towards a stationary observer at 25 m/s. If the speed of sound is 340 m/s, calculate the frequency heard by the observer.

A police car with its siren on is moving away from you. Will you hear a higher or lower pitch compared to when it is stationary?

A sound source emits a frequency of 400 Hz. If the observer moves towards the source at 20 m/s and the speed of sound is 340 m/s, what is the observed frequency?

A sound source emits at 900 Hz. The observer moves away from the source at 30 m/s, and the speed of sound is 330 m/s. What is the observed frequency?

A source emits a sound at 1200 Hz. If both the source and observer move towards each other at 20 m/s each, and the speed of sound is 340 m/s, what is the observed frequency?

A source emits sound at 1000 Hz. If the observer moves away from the source at 10 m/s and the speed of sound is 340 m/s, what is the observed frequency?

A source of sound moves at 50 m/s towards a stationary observer. The speed of sound is 350 m/s. If the source frequency is 800 Hz, what is the observed frequency?

A stationary source emits a sound at 700 Hz. An observer moves towards the source at 15 m/s. If the speed of sound is 330 m/s, what is the observed frequency?

A train approaches a platform at 30 m/s. The speed of sound is 340 m/s. If the train's whistle frequency is 500 Hz, what frequency does a stationary observer on the platform hear?

Describe one real-life example where the Doppler Effect is used in technology.

Describe the difference between the Doppler Effect for sound and for light.

Describe what happens to the wavelength of sound waves as the source moves towards the observer.

Explain the term 'redshift' in the context of the Doppler Effect for light.

Explain why the Doppler Effect does not change the speed of the wave.

Explain why the Doppler Effect is more pronounced for higher speeds of the source or observer.

Explain why the Doppler Effect is not noticeable for everyday sounds when the relative speed is very small compared to the speed of sound.

If a source moves at the speed of sound, what phenomenon occurs?

If the source of sound moves away from a stationary observer, what happens to the observed frequency?

If the speed of sound in air increases, what happens to the observed frequency for a moving source?

State the formula for the observed frequency when the source is moving towards a stationary observer.