When a car travelling with constant velocity passes a stationary observer, the observer hears a change in the frequency of sound emitted by the car. Which statement is correct ?
Correct answer: B. The greater the speed of the car, the greater the change in observed frequency.
- A. The change in frequency is greater as a car moves away than as it approaches.
- B. The greater the speed of the car, the greater the change in observed frequency.
- C. The observed frequency is lower as the car moves toward the observer and higher as the car moves away from the observer
- D. The volume of the sound heard by the observer does not change as the car approaches.
Explanation
Wave speed is the distance a wave travels in a given amount of time, such as the number of meters it travels per second. Wave speed is related to wavelength and wave frequency by the equation: Speed = Wavelength x Frequency so as the speed increases the observed frequency also increases.
Report an error
The more specific you are, the faster it gets fixed. A source beats an opinion.
Prefer email? [email protected]
About Waves
Progressive waves transfer energy through oscillations, with wavelength, frequency, amplitude and wave speed related by v = fλ; sound speed depends on the medium. Superposition produces interference and stationary waves in strings and organ pipes, while simple harmonic motion describes the oscillation itself and must be distinguished from wave propagation.
Practise Waves
1,281 free Waves MCQs from Physics, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Discussion
Stuck on an option, or know a faster way to get there? Ask or explain it here.
No comments yet. Be the first to explain this one.
Exams that ask Physics questions like this
Physics is on 16 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.
More Waves questions
In a stationary wave the distance between consecutive antinodes is 25cm. If the wave velocity is 300ms-1, then the frequency of the wave will be:
A wave of amplitude 20mm has intensity Ix. another wave of the same frequency but of amplitude 5mm has intensity Iy. What is Ix/Ty?
If the wavelength of a transverse is 2cm and the period is 2 seconds, then the wave speed in CGS is:
A tuning fork A produces 4 beats / second with another turning fork B of frequency 280 Hz. When fork A is loaded with a little wax, the beat frequency changes to 2. The frequency of fork A before loading is:
The sound waves of frequency more than 20 khz are termed as:
Velocity of sound in air is 332m/s. Velocity of sound in vacuum would be: